A caracterização de vias de sinalização alteradas em células tumorais, e a validação de fármacos inibidores de transdução de sinal que interajam com as mesmas de modo a atuar como terapia principal ou adjuvante no tratamento de neoplasias sólidas e hematopoiéticas, é um campo de grande interesse em oncologia. A necessidade da caracterização de novos alvos moleculares advém da incidência considerável de recidivas, quadros de quimiorresistência e efeitos adversos associados ao tratamento com os agentes antitumorais clássicos. Nesta tese, desenvolvemos a hipótese de que o fator de transcrição NFκB poderia estar envolvido com processos de proliferação, antiapoptose e quimiorresistência em células neoplásicas, caracterizando-se como um potencial alvo para interferência farmacológica. Para isso, avaliamos: i) o papel de NFκB na resposta celular a ERO e no controle da decisão entre morte e proliferação celular; ii) o estado de ativação de NFκB em modelos tumorais in vitro e in vivo; iii) o potencial citotóxico e seletividade dos inibidores de NFκB, seus mecanismos de ação, atividade em células neoplásicas e em linhagens quimiorresistentes. Para isso, foram utilizadas abordagens in vitro (cultivos celulares), in vivo (modelo animal de implante tumoral), e análises de bancos de expressão gênica através de ferramentas de biologia de sistemas. Os resultados demonstraram que NFκB está superestimulado em linhagens de leucemia e de glioblastoma quando comparado com leucócitos e astrócitos não-transformados. O tratamento com inibidores farmacológicos de NFκB causou morte celular programada em um mecanismo seletivo para células tumorais, potenciando os efeitos de antitumorais clássicos tanto em linhagens selvagens quanto em células quimiorresistentes. Além disso, os inibidores BAY117082 e curcumina apresentaram atividade in vivo em modelo animal de glioma sem evidência de citotoxicidade aguda. Em suma, os dados aqui apresentados sugerem que o fator de NFκB constitui-se um potencial alvo para inibição farmacológica no tratamento de neoplasias. Neste contexto, a diversidade da expressão de NFκB em diferentes tipos tumorais e a segurança associada ao uso clínico de seus inibidores permanece por ser avaliada. / Characterization of new molecular targets is one of the most important challenges in oncology. In this context, there is a growing interest in characterization of deregulated cell signaling pathways in solid and hematopoietic cancer cells in order to leverage the development of specific cell signaling inhibitors to act as principal or adjuvant therapy, and to circumvent the frequently observed chemoresistance and relapse in cancer patients. In this study, we hypothesized that the transcription factor NFκB could be involved on proliferation, antiapoptosis response and chemoresistance in cancer cells thus being a potential target for pharmacological interference. Attempting to test this, we evaluated: i) the role of NFκB in cell response against reactive oxygen species and in control of cell death and proliferation signaling; ii) NFκB activation status in cancer and noncancerous cells in vitro and in vivo; iii) cytotoxicity, selectivity and mechanisms of action of NFκB inhibitors in glioma and leukemia cells besides its biological activity against chemotherapy-resistant cell lines. Experiments were performed based on in vitro (cancer cell lines and primary cultures) and in vivo (tumor implants) models of cell growth. Moreover, in some experiments, bench-directed analysis of public gene expression databases followed by bioinformatic approach was used to ensure the significance and reliability of experimental data. Our findings showed an overstimulation of NFκB in leukemic and glioblastoma cell lines compared to healthy leucocytes and non-transformed astrocytes, respectively. Treatment with pharmacological inhibitors of NFκB induced programmed cell death in a cancer cells selective manner and potentiated the effects of classical anticancer drugs in both wild-type and chemoresistant cell lines. Indeed, the pharmacological NFκB inhibitors BAY117082 and curcumin showed significant anticancer efficacy in a model of brain-implanted gliomas without evidence of acute toxicity. Overall, the herein presented data suggest that NFκB is a potential target for cell death induction in leukemia and glioblastomas. Evaluation of its expression profile in different type of cancers beyond testing efficacy and safety of NFκB pharmacological inhibitors for clinical usefulness remains to be investigated.

A caracterização de vias de sinalização alteradas em células tumorais, e a validação de fármacos inibidores de transdução de sinal que interajam com as mesmas de modo a atuar como terapia principal ou adjuvante no tratamento de neoplasias sólidas e hematopoiéticas, é um campo de grande interesse em oncologia. A necessidade da caracterização de novos alvos moleculares advém da incidência considerável de recidivas, quadros de quimiorresistência e efeitos adversos associados ao tratamento com os agentes antitumorais clássicos. Nesta tese, desenvolvemos a hipótese de que o fator de transcrição NFκB poderia estar envolvido com processos de proliferação, antiapoptose e quimiorresistência em células neoplásicas, caracterizando-se como um potencial alvo para interferência farmacológica. Para isso, avaliamos: i) o papel de NFκB na resposta celular a ERO e no controle da decisão entre morte e proliferação celular; ii) o estado de ativação de NFκB em modelos tumorais in vitro e in vivo; iii) o potencial citotóxico e seletividade dos inibidores de NFκB, seus mecanismos de ação, atividade em células neoplásicas e em linhagens quimiorresistentes. Para isso, foram utilizadas abordagens in vitro (cultivos celulares), in vivo (modelo animal de implante tumoral), e análises de bancos de expressão gênica através de ferramentas de biologia de sistemas. Os resultados demonstraram que NFκB está superestimulado em linhagens de leucemia e de glioblastoma quando comparado com leucócitos e astrócitos não-transformados. O tratamento com inibidores farmacológicos de NFκB causou morte celular programada em um mecanismo seletivo para células tumorais, potenciando os efeitos de antitumorais clássicos tanto em linhagens selvagens quanto em células quimiorresistentes. Além disso, os inibidores BAY117082 e curcumina apresentaram atividade in vivo em modelo animal de glioma sem evidência de citotoxicidade aguda. Em suma, os dados aqui apresentados sugerem que o fator de NFκB constitui-se um potencial alvo para inibição farmacológica no tratamento de neoplasias. Neste contexto, a diversidade da expressão de NFκB em diferentes tipos tumorais e a segurança associada ao uso clínico de seus inibidores permanece por ser avaliada. / Characterization of new molecular targets is one of the most important challenges in oncology. In this context, there is a growing interest in characterization of deregulated cell signaling pathways in solid and hematopoietic cancer cells in order to leverage the development of specific cell signaling inhibitors to act as principal or adjuvant therapy, and to circumvent the frequently observed chemoresistance and relapse in cancer patients. In this study, we hypothesized that the transcription factor NFκB could be involved on proliferation, antiapoptosis response and chemoresistance in cancer cells thus being a potential target for pharmacological interference. Attempting to test this, we evaluated: i) the role of NFκB in cell response against reactive oxygen species and in control of cell death and proliferation signaling; ii) NFκB activation status in cancer and noncancerous cells in vitro and in vivo; iii) cytotoxicity, selectivity and mechanisms of action of NFκB inhibitors in glioma and leukemia cells besides its biological activity against chemotherapy-resistant cell lines. Experiments were performed based on in vitro (cancer cell lines and primary cultures) and in vivo (tumor implants) models of cell growth. Moreover, in some experiments, bench-directed analysis of public gene expression databases followed by bioinformatic approach was used to ensure the significance and reliability of experimental data. Our findings showed an overstimulation of NFκB in leukemic and glioblastoma cell lines compared to healthy leucocytes and non-transformed astrocytes, respectively. Treatment with pharmacological inhibitors of NFκB induced programmed cell death in a cancer cells selective manner and potentiated the effects of classical anticancer drugs in both wild-type and chemoresistant cell lines. Indeed, the pharmacological NFκB inhibitors BAY117082 and curcumin showed significant anticancer efficacy in a model of brain-implanted gliomas without evidence of acute toxicity. Overall, the herein presented data suggest that NFκB is a potential target for cell death induction in leukemia and glioblastomas. Evaluation of its expression profile in different type of cancers beyond testing efficacy and safety of NFκB pharmacological inhibitors for clinical usefulness remains to be investigated.

ZUSAMMENFASSUNG Obwohl diverse Mutationen des NF-κB Systems in Myelomzelllinien und primären Myelomzellen eine pathogenetische Beteiligung andeuten, ist die Relevanz des IKK Komplexes als molekularer Angriffspunkt für die Entwicklung medikamentöser Therapieoptionen noch nicht ausreichend geklärt. Zwar führte die Applikation des IKK-β Inhibitors MLN120b dosisabhängig und längerfristig zu einer Reduktion der Zellviabilität in einer Vielzahl von Myelomzelllinien, doch kann nicht ausgeschlossen werden, dass bei höheren Konzentrationen unspezifische Wirkungen für die beobachteten Effekte (mit-) verantwortlich sind. Aus diesem Grund erfolgte in der vorliegenden Arbeit eine spezifische Suppression von IKK-α, IKK-β oder IKK-γ mittels transienter Transfektion von shRNA Expressionsvektoren oder Stealth-siRNA. Es folgte die Charakterisierung der verminderten Zielproteinspiegel mittels Western-Blot und die Messung der Viabilität der Zellen mittels FACS Analysen. Darüber hinaus wurde in TNF-α Stimulationsexperimenten der Effekt der Suppression von IKK-β mittels Stealth-siRNA auf (Phospho-)IκB-α analysiert. Schließlich erfolgte die Applikation des IKK-β Inhibitors TPCA, dessen Wirkung auf die Zellviabilität und auf die TNF-α-vermittelte Phosphorylierung und Degradation von IκB-α in MM.1S Zellen untersucht wurde. Die Experimente mit Stealth-siRNA zeigten, dass weder die Suppression von IKK-β, noch die Suppression von IKK-α oder IKK-γ in AMO-1, L363 oder MM.1S eine Verminderung der Zellviabilität bewirken konnte. Auch eine kombinierte Suppression von IKK-α zusammen mit IKK-β in L363 und MM.1S Zellen bewirkte keinen vermehrten Zelltod. Dagegen zeigte die Behandlung von MM.1S Zellen mit hohen Konzentrationen von TPCA einen geringen Effekt auf das Überleben dieser Zellen. Die Suppression von IKK-β mittels Stealth-siRNA in MM.1S konnte nicht die TNF-α vermittelte IκB-α Phosphorylierung und Degradation verhindern. Sowohl die hohe TNF-α Konzentration von 100ng/ml, als auch eine unvollständige Suppression von IKK-β könnte dazu beigetragen haben. In analogen Experimenten mit TPCA konnte die TNF-α vermittelte IκB-α Phosphorylierung und Degradation dagegen effektiv unterdrückt werden. In der Zusammenschau der Ergebnisse konnte somit eine potenzielle therapeutische Relevanz des IKK-Komplexes als molekularer Angriffspunkt für eine Myelomtherapie nicht gefunden werden. Eine noch detailliertere Analyse der Funktionalität des Signalwegs (insbesondere eine Messung der Aktivität der NF-κB Transkriptionsfaktoren im Zellkern) und die Etablierung stabiler und induzierbarer Expressionssysteme für längerfristige Untersuchungen der RNAi Wirkungen in Myelomzellen, stellen weiterführende Wege zu einer umfangreicheren Beurteilung der pathobiologischen und therapeutischen Bedeutung des NF-κB Systems dar. Darüber hinaus sind die das NF-κB System betreffenden Mutationen genauer hinsichtlich ihrer potenziellen Wirkung auf NF-κB unabhängige Signalwege zu untersuchen. / ABSTRACT Although the known mutations in NF-kB in imply to view the IKK complex to be involved in promoting survival of Multiple Myeloma cells, and IKK-beta inhibitors have been reported to show anti-Myeloma activity, the actual significance of IKK as a molecular target for treatment of the desease remains unclear. This is due to the fact that the influence on survival by pharmacological inhibitors on many Multiple Myeloma cells has been shown to be dependend on high concentration applications and on long-term incubation times, both inheriting the possibility of unspecific drug effects. Therefor we chose an alternative approach and performed a RNAi mediated knockdown of each of the three components of the IKK Complex (IKK-alpha, IKK-beta and IKK-gamma) and measured the survival rate of the Multiple Myeloma celllines AMO-1, L363 and MM.1s. None of the knockdowns led to a decrease of Multiple Myeloma survival rate, and even a combined knockdown of IKK-alpha and IKK-beta in L363 and MM.1S showed significant effects on the survival. Summarized, IKK is not crucially involved in promoting survival of the mentioned Multiple Myeloma celllines and thus the relevance of the complex as a therapeutic target for the treatment of Multiple Myeloma is not thoroughly clarified yet. Further investiations in different celllines and RNAi mediated knockdowns in longer time intervalls might resolve the true significance of IKK for Myeloma survival.

The aim of this study was to determine whether there is an influence of the active components of the fish oil, in particular polyunsaturated fatty acids n3 (PUFA n3) on expression of selected proteins which modulate the inflammatory response in model organisms pig. In the n3 PUFA is to assume that over signaling pathway PPARgamma, NFkappaB, increase adiponectin production, inhibit the production of proinflammatory cytokines, increase antiinflammatory cytokines production, thereby suppressing the inflammatory response in the body. This hypothesis was tested on 32 pigs, which were divided into two groups of 16 pieces in each group. The first experimental group was fed the basic feed mixture enriched with 2.5% fish oil (F) and the second control group was fed the basic feed with 2.5% palm oil (P). Last day of fattening pigs were 8 F and 8 P pigs intravenously application lipopolysaccharide (LPS) to induce an inflammatory response, the rest of group left without LPS stimulation, followed by intramuscular application of anesthetics and defeat. By Western blot was measured protein expression PPARgamma and NFkappaB in selected tissues, by ELISA concentration of adiponectin in plasma and by multiplex analysis plasma levels of cytokines. The results indicate that PPARgamma concentration in the F adipocytes after LPS stimulation tended to increase by 21% in comparison with P control stimulation with LPS, but the result was not statistically significant (P> 0.05; P = 0.11). Further, the F pigs stimulation with LPS as compared with intact F counterparts trend toward increased plasma levels of adiponectin by 18%, which was likely a reflection of the tendency to higher values in adipocytes by 18% (P> 0.05, p = 0.12), result was not statistically significant. Plasma adiponectin took on the same values of 21.1 ng x mL-1 in experimental and control groups (P> 0.05). Elevation (P <0.05) of NFkappaB in fatty tissue F pigs after LPS stimulation. In addition, the plasma level of anti-inflammatory IL4 and IL10 interleukins, as well as the proinflammatory cytokine TNFalfa, was increased (P <0.05) in the F group of pigs stimulated with LPS. The results of the present experiment are thus ambiguous. The hypothesis of the effect of fish oil or n3 PUFA to suppress the inflammatory response cannot this experiment conclusively confirmed.

No description available.

No description available.

Opioid receptor modulation of pro-inflammatory cytokine production is vital for host defense and the inflammatory response. Previous results have shown the mu-opioid receptor (MOR) selective agonist, DAMGO, has the capacity to increase the expression of the pro-inflammatory chemokines, CCL2/MCP-1, CCL5/RANTES and CXCL10/IP-10 in peripheral blood mononuclear cells (PBMCs). We have shown that MOR activation is able to induce the expression of TGF-β, and TGF-β appears to be required for induction of CCL5 following MOR activation. This work suggests a novel role for TGF-β in the inflammatory response. NF-κB is a transcription factor that plays a pivotal role in inflammation and the immune response. We have found that NF-kB inhibitors can prevent the MOR-induced activation of CCL2 and CCL5, and that the NF-kB subunit, p65, is phosphorylated at serine residues 311 and 536 in response to μ-opioid receptor activation. In vivo, DAMGO administration can induce binding of p. 65 to the enhancer region of the CCL2 promoter. Furthermore, we demonstrate that PKCζ is phosphorylated following DAMGO-induced MOR activation and, is essential for NF-kB activity as well as CCL2 expression and transcriptional activity. In conclusion, these data suggest a pro-inflammatory role for MOR which involves NF-κB activation and PKCζ as well as a novel role for TGF-β as a regulator of pro-inflammatory chemokines. / Molecular Biology and Genetics

Titre de l'écran-titre (visionné le 23 mai 2023) / Contexte : La génétique a une implication majeure dans la pathogenèse de la parodontite. Elle fait d'ailleurs l'objet d'un nombre grandissant de recherches qui tentent d'identifier quels facteurs prédisposent au développement de la maladie, mais également à une réponse réduite à la thérapie. Le facteur nucléaire kappa-B (NF-κB) a été identifié dans plusieurs maladies inflammatoires comme étant la principale voie de signalisation permettant l'activation de l'inflammation. Par ailleurs, toute altération génétique (mutation, polymorphisme ou encore modification épigénétique) de cette voie de signalisation est étroitement liée à certaines maladies inflammatoires. Objectif : L'objectif du projet est (1) d'étudier si le polymorphisme génétique de NF-κB est associé au développement de la parodontite dans la population québécoise; et (2) de vérifier s'il est associé à une réponse altérée à la thérapie parodontale non chirurgicale. Matériel et méthodes : 200 échantillons salivaires ont été obtenus auprès de patients québécois de la clinique de parodontite de la Faculté de médecine dentaire de l'Université Laval et l'ADN de chaque échantillon a été isolé. Quatre SNP de NF-κB ont été choisis pour génotypage : rs4648127, rs4648099, rs4648072, rs4648065. L'ADN a été extrait avec la trousse de Qiagen et quantifié avec NanoDrop. Le génotypage a été réalisé par une réaction en chaîne par polymérase (PCR) grâce à la technique de génotypage TaqMan utilisée pour amplifier et détecter des allèles spécifiques de chaque polymorphisme sélectionné de NF-κB dans l'ADN génomique (ADNg). Résultats : 146 échantillons ont pu être analysés. Le groupe test (parodontite) était formé de 58 participants tandis que le groupe contrôle en comptait 88. Le seul polymorphisme ayant montré des variations entre les sujets est rs4648127. Le génotype CT était associé au développement de la parodontite (OR = 1,04, p > 0,05), mais le résultat n'était pas statistiquement significatif. Des analyses de sous-groupe ont été réalisées pour vérifier les différences entre les hommes, les femmes et différentes tranches d'âge. Aucune valeur statistiquement significative n'a été trouvée. Les concentrations salivaires de TNF-α à la base de référence n'étaient pas les mêmes entre les groupes test et contrôle (test : 42,43 pg/mL, contrôle : 25,34 pg/mL, p = 0,000952). Concernant la réponse à la thérapie, les concentrations salivaires de TNF-α ont diminué de manière significative entre le début et le contrôle postopératoire (base de référence : 42,43 pg/mL, post-op : 28,19 pg/mL, p = 0,00435). L'écart dans la réponse à la thérapie chez les patients présentant un génotype CC ou CT n'ont pas montré de différences statistiques. Conclusion : Les polymorphismes de NF-κB (rs4648127, rs4648099, rs4648072, rs4648065) ne semblent pas associés ni au développement de la parodontite, ni à une réponse altérée à la thérapie parodontale chez les adultes québécois. Cependant, d'autres études avec de plus larges échantillons sont nécessaires pour tirer de plus franches conclusions sur ces résultats. / Introduction: The nuclear factor kappa-B (NF-κB) has been identified in several inflammatory diseases as the main signaling pathway responsible for the activation of inflammation. Furthermore, this factor's genetic variations (polymorphisms) have been associated with inflammatory diseases. Therefore, this study aimed to (1) search for the implication that polymorphisms of NF-κB have in the development of periodontitis in adults from the province of Quebec, Canada and (2) verify if different allele frequencies can affect the outcomes of the non-surgical periodontal therapy. Methods: 200 saliva samples were obtained and studied using a genotyping assay to verify the association between periodontitis and four single nucleotide polymorphisms (SNPs): rs4648127, rs4648099, rs4648072, rs4648065. DNA was extracted using a Qiagen kit and quantified by NanoDrop One. Genotyping was realized by TaqMan Real-Time PCR Assays. The reduction in inflammation following therapy was measured by comparing saliva concentration of tumor necrosis factor-α (TNF-α) at the baseline and four to eight weeks after the treatment. Results: 146 samples were subject to analysis. As 58 and 88 patients were forming the test (periodontitis) and control groups, respectively. Only the rs4648127 SNP varied between subjects. CT genotype was associated with the development of periodontitis (OR = 1.04, p > 0.05) but was not statistically significant. Subgroup analysis were done to search for associations in male, female, and different age groups but were not statistically significant. Baseline TNF-α concentration in saliva showed variations between test and control groups (test: 42.43 pg/mL, control: 25.34 pg/mL p = 0.000952). The level of inflammation reduced after therapy. The concentration of TNF-α was 42.43 pg/mL at baseline and 28.19 pg/mL after treatment (p = 0.00435). No significant results were found between subjects with CT genotype or CC genotype. Conclusion: Either the development of periodontitis or the reduction in inflammation after therapy is associated with NF-κB polymorphisms in adults from Quebec. However, other studies with larger samples are needed to confirm those results.

O perfil de ativação do NF-B foi avaliado em biópsias de 47 pacientes com diagnóstico clínico e laboratorial de hanseníase, seguidos no Ambulatório de Hanseníase do Centro de Referência Nacional em Dermatologia Tropical com Ênfase em Hanseníase do Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto Universidade de São Paulo. O índice de ativação NF-B foi calculado de acordo com a porcentagem de positividade na histoquímica Southwestern. Índice de ativação NF-B >1 foi considerado representativo de ativação. Trinta e seis por cento dos pacientes apresentaram NF-B ativado na biópsia, o que foi mais frequente em multibacilares (54,6%) que em paucibacilares (20%), p=0,018. Hanseníase tuberculóide esteve associada com ausência de NF-B ativado (p=0,039). Forma dimorfa e neural pura estiveram associadas com ativação de NF-B, com odds ratio de 44 (p=0,014) e 30 (p=0,029), respectivamente. A ativação correlacionou-se com detecção in situ de fator de necrose tumoral por imuno-histoquímica (p=0,0064). Observou-se grande variação da ativação do NF-B nas formas clínicas de hanseníase. Ativação foi nula em granulomas de hanseníase tuberculóide, que representa a reação inflamatória mais efetiva contra o M. leprae. A ativação do NF-B ocorreu predominantemente em formas clínicas com maior suscetibilidade (multibacilares) e instabilidade imunológica (dimorfa), indicando condição favorável à infecção pela ativação do NF-B, por seus efeitos antiapoptóticos, visto que o bacilo depende das funções celulares para sobreviver. / NF-B activation profile was evaluated in cutaneous biopsies from 47 patients with clinical and laboratorial diagnosis of leprosy followed at a referral center for treatment of leprosy, the leprosy outpatient clinic of the Hospital of Clinics of Faculty of Medicine of Ribeirão Preto University of São Paulo. NF-B activation index (ranging from 0 to 4) was calculated according to the percentage of positivity in Southwestern histochemistry. Activation index >1 was considered representative of activation. Thirty-six percent of patients presented activated NF-B, which was more frequent in multibacillary (54,6%) than in paucibacillary (20%), p=.018. Tuberculoid leprosy was associated with absence of activated NF-B (p=.039). Borderline and pure neural leprosy clinical forms were associated with NF-B activation, with odds ratio of 44 (p=.014) and 30 (p=.029), respectively. NF-B activation was correlated with in situ detection of tumor necrosis factor- by immunohistochemistry (p=.0064). Great variation of NF-B activation was found in clinical forms of leprosy. Activation was absent in tuberculoid leprosys granulomas, which represent effective inflammatory reaction pattern against M. leprae. NF-B activation was present in clinical forms with increased susceptibility (multibacillary) and immunological instability (borderline), which suggests favorable conditions towards infection, probably due to the anti-apoptotic effects of NF-B, since bacillary survival is dependent of cellular functions.

O excesso de adenina na dieta (ADE) promove precipitação intratubular de cristais, levando à instalação de uma nefrite intersticial progressiva e perda da função renal. Observações recentes indicam que a sobrecarga de ADE em camundongos em que os genes para TLR-2, -4, MyD88, ASC ou caspase-1 foram inativados provoca menos dano renal do que quando administrado a camundongos selvagens, sugerindo a existência de um papel patogênico para a ativação de TLRs e a montagem de inflamassomas nesse modelo. O presente estudo foi concebido para investigar se outro importante componente da imunidade inata, o sistema NF-B, também exerce papel patogênico na nefropatia associada ao excesso de ADE. Ratos Munich-Wistar machos e adultos foram divididos em 3 grupos: C (N=17), ração padrão; ADE (N=17), ADE na ração, 0,7% durante 1 semana e 0,5% durante 2 semanas; ADE+PDTC (N=14), ADE administrada como descrito anteriormente, associada ao inibidor do NF-B, pirrolidina ditiocarbamato (PDTC), 120 mg/kg/dia na água do bebedouro. Após 3 semanas, observou-se deposição de numerosos cristais no tecido renal, em sua maioria no interior de granulomas de corpo estranho, acompanhada de intensa atividade proliferativa tubulointersticial. Uma parte dos cristais apareceu envolvida por uma camada de células aparentemente derivadas do epitélio tubular, que pareciam segregar os precipitados e, em alguns casos, expulsá-los ao interstício. Essas alterações associaram-se a uma grande expansão da área intersticial, com deposição de colágeno, além de hipotrofia glomerular. Foi possível ainda demonstrar um aumento da expressão da interleucina-6, do interferon-, da proteína específica de fibroblastos (FSP-1) e da proteína quimiotática para macrófagos (MCP-1). A abundância do IKK-, uma quinase ativadora do sistema NK-B, mostrou-se também acentuadamente elevada nesses ratos. O tratamento com PDTC normalizou a expressão do IKK-, diminuindo o número de granulomas e a proliferação celular, além de atenuar fortemente a fibrose e o declínio da função renal. Esses achados, que contribuem para elucidar os mecanismos de formação de granulomas no modelo de sobrecarga de adenina, são consistentes com o conceito de que o sistema NF-B é ativado pela precipitação intratubular de cristais e contribui, juntamente com outros mecanismos ligados à imunidade inata, para iniciar a intensa resposta inflamatória associada a esse modelo. Descritores: 1.Insuficiência renal crônica 2.Adenina 3.Imunidade inata 4.NF-kappa B 5.GranulomaO excesso de adenina na dieta (ADE) promove precipitação intratubular de cristais, levando à instalação de uma nefrite intersticial progressiva e perda da função renal. Observações recentes indicam que a sobrecarga de ADE em camundongos em que os genes para TLR-2, -4, MyD88, ASC ou caspase-1 foram inativados provoca menos dano renal do que quando administrado a camundongos selvagens, sugerindo a existência de um papel patogênico para a ativação de TLRs e a montagem de inflamassomas nesse modelo. O presente estudo foi concebido para investigar se outro importante componente da imunidade inata, o sistema NF-B, também exerce papel patogênico na nefropatia associada ao excesso de ADE. Ratos Munich-Wistar machos e adultos foram divididos em 3 grupos: C (N=17), ração padrão; ADE (N=17), ADE na ração, 0,7% durante 1 semana e 0,5% durante 2 semanas; ADE+PDTC (N=14), ADE administrada como descrito anteriormente, associada ao inibidor do NF-B, pirrolidina ditiocarbamato (PDTC), 120 mg/kg/dia na água do bebedouro. Após 3 semanas, observou-se deposição de numerosos cristais no tecido renal, em sua maioria no interior de granulomas de corpo estranho, acompanhada de intensa atividade proliferativa tubulointersticial. Uma parte dos cristais apareceu envolvida por uma camada de células aparentemente derivadas do epitélio tubular, que pareciam segregar os precipitados e, em alguns casos, expulsá-los ao interstício. Essas alterações associaram-se a uma grande expansão da área intersticial, com deposição de colágeno, além de hipotrofia glomerular. Foi possível ainda demonstrar um aumento da expressão da interleucina-6, do interferon-, da proteína específica de fibroblastos (FSP-1) e da proteína quimiotática para macrófagos (MCP-1). A abundância do IKK-, uma quinase ativadora do sistema NK-B, mostrou-se também acentuadamente elevada nesses ratos. O tratamento com PDTC normalizou a expressão do IKK-, diminuindo o número de granulomas e a proliferação celular, além de atenuar fortemente a fibrose e o declínio da função renal. Esses achados, que contribuem para elucidar os mecanismos de formação de granulomas no modelo de sobrecarga de adenina, são consistentes com o conceito de que o sistema NF-B é ativado pela precipitação intratubular de cristais e contribui, juntamente com outros mecanismos ligados à imunidade inata, para iniciar a intensa resposta inflamatória associada a esse modelo / Excessive dietary adenine (ADE) promotes intratubular precipitation of crystals, leading to the installation of progressive interstitial nephritis and renal function loss. Recent observations indicate that ADE overload in mice in which genes for TLR-2, -4, MyD88, ASC or caspase-1 were inactivated causes less renal damage than when administered to wild-type mice, suggesting the existence of a pathogenic role for the activation of TLRs and the assembly of inflamassomes in this model. The present study was designed to investigate whether another important component of innate immunity, the NF-B system, also plays a role in the pathogenesis of the nephropathy associated with excess ADE. Adult Male Munich-Wistar rats were distributed among three groups: C (n = 17), receiving standard diet; ADE (N = 17), given ADE in the diet at 0.7% for 1 week and 0.5% for 2 weeks; and ADE + PDTC (N = 14), receiving ADE as described above, associated with the NF-B inhibitor, pyrrolidine dithiocarbamate (PDTC), 120 mg/kg/ day in drinking water. After three weeks, there was widespread deposition of crystals in the renal tissue, mostly within granulomas, accompanied by florid tubulointerstitial proliferative activity. Part of these crystals was enclosed in a layer of cells apparently derived from the tubular epithelium, which appeared to segregate the precipitates, and in some cases, to extrude them to the interstitium. These changes were associated with marked interstitial expansion, collagen deposition, and glomerular hypotrophy. Increased expression of interleukin-6, interferon-, fibroblast specific protein (FSP-1) and macrophage chemoattractant protein (MCP-1) were also shown. The abundance of IKK-, a kinase that activates the NF-B system, was also markedly elevated in these mice. Treatment with PDTC normalized the expression of IKK-, reducing the number of granulomas and cell proliferation, and strongly attenuated interstitial fibrosis and the decline of renal function. These findings, which contribute to illuminate some mechanisms of granuloma formation in the ADE overload model, are consistent with the concept that the NF-B system is activated by intratubular precipitation of crystals and contributes, along with other mechanisms related to innate immunity, to initiate the intense inflammatory response associated with this model