MyD88 est une protéine adaptatrice du système immunitaire inné, impliquée dans la défense de l’organisme contre les agents microbiens. Elle est recrutée aux « Toll-like receptors » (TLRs) suite à la reconnaissance par ces derniers de motifs microbiens conservés, les PAMPs (Pathogens-associated molecular patterns). La voie de signalisation ainsi déclenchée va aboutir à la production de cytokines pro-inflammatoires, de chimiokines et d’espèces actives de l’oxygène. De cette façon, les TLRs, via MyD88, constituent la première ligne de défense contre les pathogènes.De nombreuses études ont permis de démontrer que MyD88 est nécessaire pour la réponse inflammatoire, qui promeut la carcinogenèse. Dans le cadre d’une étude sur les TLRs et le cancer, l’équipe a démontré, grâce à une étude in vivo, que MyD88 participe au processus de tumorigenèse médiée par l’oncogène ras et est nécessaire à l’activation de la voie canonique des MAPKs, ainsi qu’à la transformation cellulaire in vitro. Nous avons ensuite déterminé le mécanisme par lequel MyD88 intervient dans la voie de signalisation Ras/MAPKs, en permettant le maintien de l’activation de cette voie. En effet, MyD88 interagit avec une MAPK clé de cette voie : la kinase ERK, et protège cette dernière de sa déphosphorylation par sa phosphatase spécifique MKP-3, MyD88 et MKP-3 se liant à ERK par le même domaine. Nous avons démontré la pertinence de ce mécanisme, grâce à la mise en évidence d’une surexpression de la protéine MyD88 et de son interaction avec la forme phosphorylée d’ERK dans des coupes de tissus tumoraux humains (estomac, poumon, colon).L’ensemble des résultats obtenus au cours de ma thèse ont permis de montrer qu’en plus de son rôle bien défini en tant qu’adaptateur des récepteurs de l’immunité innée dans les processus inflammatoires, MyD88 joue un rôle direct, qui semble être crucial dans la signalisation Ras, le contrôle du cycle cellulaire et la transformation cellulaire / MyD88 is an adaptator protein of the innate immune system, implicated in the défense against microbes. MyD88 is recruited by the Toll-Like Receptors (TLRs) upon there interaction with conserved microbial patterns (PAMPs). Therefore, TLR signaling pathway induces the production of pro-inflammatory cytokines, chemokines and reactive oxygen species. TLRs, via MyD88, form the first line of defense against pathogens. Accumulating evidence points to inflammation as a promoter of carcinogenesis. MyD88 is an adaptor molecule in TLR and IL-1R signaling that was recently implicated in tumorigenesis through proinflammatory mechanisms. Here we have shown that MyD88 is also required in a cell-autonomous fashion for Ras-mediated carcinogenesis in mice in vivo and for MAPK activation and transformation in vitro. Mechanistically, MyD88 bound to the key MAPK, ERK, and prevented its inactivation by its phosphatase, MKP3, thereby amplifying the activation of the canonical Ras pathway. The relevance of this mechanism to human neoplasia was suggested by the finding that MyD88 was overexpressed and interacted with activated ERK in primary human cancer tissues. Collectively, these results show that in addition to its role in inflammation, MyD88 plays what we believe to be a crucial direct role in Ras signaling, cell-cycle control, and cell transformation

O Diabete tipo 2 é uma síndrome heterogênea caracterizada por resistência à insulina e /ou diminuição relativa da função secretora das células &#946; pancreáticas. Os Diabéticos têm risco maior de desenvolver aterosclerose, que é uma doença inflamatória crônica que envolve a resposta imune. Os TLRs sinalizadores da resposta imune inata que ativam vias que participam na regulação da inflamação podem estar associados com a patogênese da aterosclerose. Além disso, são capazes de induzir a resistência à insulina. Estudos sugerem que a inflamação é um fator chave na aterogênese em diabéticos tipo 2. Citocinas pró-inflamatórias, como a IL-6 e o TNF-&#945;, são produzidas pelo tecido adiposo em grande quantidade em indivíduos obesos, especialmente em pacientes com DM2. Este estudo tem por objetivo avaliar a associação dos genes do TLR2, TLR4, TNF-&#945; e IL-6 com o diabetes tipo 2 e com a aterosclerose. Foram selecionados sessenta e um indivíduos DM2 e trinta e nove indivíduos normoglicêrmicos (grupo controle) na seção de Coronárias do Instituto Dante Pazzanese de Cardiologia (São Paulo, Brasil). O ultra-som de carótida foi utilizado para avaliar a presença de aterosclerose. Os polimorfismos dos genes TLR4 (Thr399lle), TLR2 (Arg753Gln), and IL6 (-174G>C) foram identificados pela PCR-RFLP. O polimorfismo dos genes TLR4 (Asp299Gly) and TNF-&#945; (-308G>A) foram detectados por HRM. A expressão do mRNA nos leucócitos do sangue periférico foi mensurado pela PCR em tempo real utilizando o gene GAPD como gene referência. No grupo diabéticos, indivíduos portadores do alelo IL-6 -174C apresentaram colesterol total, VLDL-C e triglicérides que os portadores do genótipo GG (respectivamente, p=0,007, p=0,006 e p= 0,030). A expressão de TLR4 foi maior em indivíduos do grupo diabéticos que no grupo controle (p=0,029). Em DM2, o genótipo TNF-&#945; -308GG foi associado com o aumento da expressão do mRNA do gene TNF-&#945; (p=0,031) e maiores concentrações de fibrinogênio que os portadores do alelo -308A (genótipo GA+AA) (p=0,020). Em indivíduos com aterosclerose o alelo TLR4 299Gly foi associado com altas concentrações de glicemia pós 75g de glicose (p=0,012). E portadores do alelo IL6 -174C apresentaram maiores concentrações de colesterol total e LDL-C que nos portadores do genótipo GG (ambos p<0,001). O polimorfismo -174G>C (alelo C) e o DM2 mostraram serem fatores de risco para a aterosclerose (odds ratio respectivamente: 3,0 and 16,962). E, o sexo masculino e a menopausa mostraram serem fatores de risco para o DM2. / Type 2 diabetes is an heterogeneous syndrome characterized by the resistance to insulin and/or relative decrease of the secretion of insulin of the pancreatic &#946; cells. T2DM are in high risk of develop atherosclerosis, that is a chronic inflammatory disease involving immune response. Many existing in the atherosclerotics plaques the TLRs are signaling for immune innate response, that activate inflammatory cells involved in progression of atherosclerotic disease. TLRs can be also associated with induction of the resistance to insulin. Many studies have been suggesting that inflammation is a key factor of the progression of atherosclerotic disease in type 2 diabetes. Proinflammatory cytokines, such as IL-6 and TNF-&#945;, are produced by the adipose tissue in high concentration in obese individuals, mainly among patients with T2DM. This study aims to investigate the relationship between TLR2, TLR4, TNF-&#945; and IL-6 gene expression and polymorphisms with T2DM and atherosclerosis. Sixty-one T2DM and thirty nine normoglycemic (control group) individuals were selected at the Coronary Session of the Instituto Dante Pazzanese de Cardiologia (Sao Paulo, Brazil). Carotid artery ultrassonography was used to evaluate the atherosclerotic status. Polymorphisms of TLR4 (Thr399lle), TLR2 (Arg753Gln), and IL6 (-174G>C) genes were detected by PCR-RFLP. TLR4 (Asp299Gly) and TNFA (-308G>A) gene polymorphisms were detected by HRM. Blood leukocytes mRNA expression was measured by real time PCR using GAPD as a reference gene. In T2DM, individuals carrying IL6 -174C allele had higher total cholesterol, VLDL-c and triglycerides than the genotype GG carriers (respectively, p=0,007, p=0,006 and p= 0,030). TLR4 mRNA expression was higher in T2DM than in control individuals (p=0,029). In T2DM group, TNF-&#945; -308GG genotype was associated with increased TNF-&#945; mRNA expression levels (p=0,031) and higher fibrinogen levels than those carrying -308A allele (GA+AA genotypes) (p=0,020). In individuals with atherosclerosis TLR4 299Gly allele was associated with high post-test glucose levels (p=0,012). And carrying IL6 -174C allele had higher total cholesterol and LDL-C than the genotype GG carriers (both p<0,001). The polymorphism -174G>C and the T2DM was related with risk for atherosclerosis (odds ratio respectively: 3,0 and 16,962) and, the male sex and menopause was related with risk for T2DM (odds ratio respectively: 3,401 and 3,025).

O Diabete tipo 2 é uma síndrome heterogênea caracterizada por resistência à insulina e /ou diminuição relativa da função secretora das células &#946; pancreáticas. Os Diabéticos têm risco maior de desenvolver aterosclerose, que é uma doença inflamatória crônica que envolve a resposta imune. Os TLRs sinalizadores da resposta imune inata que ativam vias que participam na regulação da inflamação podem estar associados com a patogênese da aterosclerose. Além disso, são capazes de induzir a resistência à insulina. Estudos sugerem que a inflamação é um fator chave na aterogênese em diabéticos tipo 2. Citocinas pró-inflamatórias, como a IL-6 e o TNF-&#945;, são produzidas pelo tecido adiposo em grande quantidade em indivíduos obesos, especialmente em pacientes com DM2. Este estudo tem por objetivo avaliar a associação dos genes do TLR2, TLR4, TNF-&#945; e IL-6 com o diabetes tipo 2 e com a aterosclerose. Foram selecionados sessenta e um indivíduos DM2 e trinta e nove indivíduos normoglicêrmicos (grupo controle) na seção de Coronárias do Instituto Dante Pazzanese de Cardiologia (São Paulo, Brasil). O ultra-som de carótida foi utilizado para avaliar a presença de aterosclerose. Os polimorfismos dos genes TLR4 (Thr399lle), TLR2 (Arg753Gln), and IL6 (-174G>C) foram identificados pela PCR-RFLP. O polimorfismo dos genes TLR4 (Asp299Gly) and TNF-&#945; (-308G>A) foram detectados por HRM. A expressão do mRNA nos leucócitos do sangue periférico foi mensurado pela PCR em tempo real utilizando o gene GAPD como gene referência. No grupo diabéticos, indivíduos portadores do alelo IL-6 -174C apresentaram colesterol total, VLDL-C e triglicérides que os portadores do genótipo GG (respectivamente, p=0,007, p=0,006 e p= 0,030). A expressão de TLR4 foi maior em indivíduos do grupo diabéticos que no grupo controle (p=0,029). Em DM2, o genótipo TNF-&#945; -308GG foi associado com o aumento da expressão do mRNA do gene TNF-&#945; (p=0,031) e maiores concentrações de fibrinogênio que os portadores do alelo -308A (genótipo GA+AA) (p=0,020). Em indivíduos com aterosclerose o alelo TLR4 299Gly foi associado com altas concentrações de glicemia pós 75g de glicose (p=0,012). E portadores do alelo IL6 -174C apresentaram maiores concentrações de colesterol total e LDL-C que nos portadores do genótipo GG (ambos p<0,001). O polimorfismo -174G>C (alelo C) e o DM2 mostraram serem fatores de risco para a aterosclerose (odds ratio respectivamente: 3,0 and 16,962). E, o sexo masculino e a menopausa mostraram serem fatores de risco para o DM2. / Type 2 diabetes is an heterogeneous syndrome characterized by the resistance to insulin and/or relative decrease of the secretion of insulin of the pancreatic &#946; cells. T2DM are in high risk of develop atherosclerosis, that is a chronic inflammatory disease involving immune response. Many existing in the atherosclerotics plaques the TLRs are signaling for immune innate response, that activate inflammatory cells involved in progression of atherosclerotic disease. TLRs can be also associated with induction of the resistance to insulin. Many studies have been suggesting that inflammation is a key factor of the progression of atherosclerotic disease in type 2 diabetes. Proinflammatory cytokines, such as IL-6 and TNF-&#945;, are produced by the adipose tissue in high concentration in obese individuals, mainly among patients with T2DM. This study aims to investigate the relationship between TLR2, TLR4, TNF-&#945; and IL-6 gene expression and polymorphisms with T2DM and atherosclerosis. Sixty-one T2DM and thirty nine normoglycemic (control group) individuals were selected at the Coronary Session of the Instituto Dante Pazzanese de Cardiologia (Sao Paulo, Brazil). Carotid artery ultrassonography was used to evaluate the atherosclerotic status. Polymorphisms of TLR4 (Thr399lle), TLR2 (Arg753Gln), and IL6 (-174G>C) genes were detected by PCR-RFLP. TLR4 (Asp299Gly) and TNFA (-308G>A) gene polymorphisms were detected by HRM. Blood leukocytes mRNA expression was measured by real time PCR using GAPD as a reference gene. In T2DM, individuals carrying IL6 -174C allele had higher total cholesterol, VLDL-c and triglycerides than the genotype GG carriers (respectively, p=0,007, p=0,006 and p= 0,030). TLR4 mRNA expression was higher in T2DM than in control individuals (p=0,029). In T2DM group, TNF-&#945; -308GG genotype was associated with increased TNF-&#945; mRNA expression levels (p=0,031) and higher fibrinogen levels than those carrying -308A allele (GA+AA genotypes) (p=0,020). In individuals with atherosclerosis TLR4 299Gly allele was associated with high post-test glucose levels (p=0,012). And carrying IL6 -174C allele had higher total cholesterol and LDL-C than the genotype GG carriers (both p<0,001). The polymorphism -174G>C and the T2DM was related with risk for atherosclerosis (odds ratio respectively: 3,0 and 16,962) and, the male sex and menopause was related with risk for T2DM (odds ratio respectively: 3,401 and 3,025).

Στόχος της παρούσας ερευνητικής εργασίας είναι να διερευνηθεί η επίδραση της ιμικουϊμόδης, ενός τοπικώς εφαρμοζόμενου στο δέρμα αγωνιστού των Toll-like 7 υποδοχέων (Τoll-like receptors, ΤLRs), στην συστηματική ανοσία σε ασθενείς με δερματικές HSV και HPV λοιμώξεις. Πιο αναλυτικά θέλουμε να διερευνήσουμε μήπως η τοπική χορήγηση ιμικουϊμόδης μπορεί να επηρεάσει τις κυτταροκίνες που συμμετέχουν στους μηχανισμούς φυσικής και επίκτητης ανοσίας και τους κυτταρικούς πληθυσμούς και όπως είναι τα Τ κύτταρα (βοηθητικά, κυτταροτοξικά, παρθενικά, μνήμης, ενεργοποιημένα και ρυθμιστικά), τα Β κύτταρα και τα φυσικά φονικά κύτταρα (ΝΚ). Οι TLRs είναι ο συνδετικός κρίκος μεταξύ φυσικής και επίκτητης ανοσίας εφόσον είναι οι υποδοχείς που αναγνωρίζουν και προσδένουν μοριακές δομές των παθογόνων (pathogen associated molecular patterns-PAMPs). Η έκφραση TLRs έχει εντοπιστεί σε πολλούς κυτταρικούς όπως ουδετερόφιλα, μακροφάγα, δεντριτικά κύτταρα, ενδοθηλιακά κύτταρα της δερμίδας, επιθηλιακά κύτταρα των βλεννογόνων, Β και Τ κύτταρα. Η ενεργοποίηση των TLRs οδηγεί σε έκκριση κυτταροκινών και χημειοκινών που έχουν σαν στόχο την ενεργοποίηση της φυσικής ανοσίας, που προκαλεί τελικά την δημιουργία της επίκτητης ανοσίας. Οι ιμιδαζοκινολίνες συνιστούν μία κατηγορία νουκλεοσιδικών αναλόγων που αναπτύχθηκαν σαν αντιϊκοί παράγοντες. Η ιμικουϊμόδη είναι ένας εκπρόσωπος των ιμιδαζοκινολινών που χρησιμοποιείται για την θεραπεία των κονδυλωμάτων και των επιθηλιακών καρκίνων του δέρματος. Η ιμικουϊμόδη (imiquimod) είναι προσδέτης των TLRs - πιο ειδικά του TLR-7 και χορηγείται τοπικά υπό την μορφή αλοιφής. Έχει χαρακτηριστεί σαν ανοσορρυθμιστικός παράγοντας, γιατί μέσω της πρόσδεσης της στον TLR-7 προκαλεί ένα σύνολο αντιδράσεων όπως η αύξηση της κυτταροτοξικότητας των φυσικών φονικών κυττάρων (ΝΚ), η ενεργοποίηση των μακροφάγων να εκκρίνουν κυτταροκίνες, η ενεργοποίηση και η μετανάστευση των κυττάρων του Langerhans από το δέρμα στους λεμφαδένες και η επαγωγή του πολλαπλασιασμού και της διαφοροποίησης των Τ και Β κυττάρων. Επί του παρόντος παραμένει άγνωστο αν η τοπικώς εφαρμοζόμενη ιμικουϊμόδη είναι σε θέση να εξασκεί επιπλέον της τοπικής και συστηματική ανοσοτροποποιητική δράση. Για τον λόγο αυτό στην παρούσα εργασία μελετήσαμε την επίδραση της ιμικουϊμόδης στο ανοσοποιητικό σύστημα υγιών μαρτύρων και ασθενών με HSV και HPV λοιμώξεις τόσο σε επίπεδο κυτταροκινών με την μέθοδο Cytometric bead array (CBA) όσο και σε επίπεδο κυκλοφορούντων κυτταρικών πληθυσμών στο περιφερειακό αίμα με κυτταρομετρία ροής (FACS). Τα αποτελέσματα μας υποδεικνύουν ότι η τοπική εφαρμογή της ιμικουϊμόδης είναι ικανή να προκαλέσει συστηματική ανοσοτροποποίηση και αυτό αποτελεί μια νέα και αποτελεσματική εναλλακτική θεραπεία. / In this study we investigate the influence of imiquimod, a topical applicable agonist of Toll-like receptor 7 (TLR7) in skin, on systemic immunity of patients with herpes simplex virus (HSV) and human papilloma virus (HPV) infections. We investigated whether the topical application of imiquimod affects cytokines which participate in mechanisms of innate and adaptive immune responses and cell populations, such as T-cells (helper, cytotoxic, naïve, memory, activated and regulatory), B-cells and natural killer cells (NK cells). TLRs help to bridge the gap between innate and adaptive immunity, since they recognize and bind pathogen associated molecular patterns of pathogens. The expression of TLRs has been detected on neutrophils, macrophages, dendritic cells, dermal endothelial cells, mucosal epithelial cells, T and B cells. Activation of TLRs mediates the release of cytokines and chemokines that recruit innate immune responses, which lead to the formation of adaptive immunity. Imidazoquinolines represent a group of nucleoside analogues that have been used as antiviral agents. Imiquimod belongs to imidazoquinolines and it has been used for the treatment of genital warts (caused by HPV) and cutaneous cancers. Imiquimod is a ligand of TLR7 and a patient-applied cream. It has been characterized as an immune response modifier, because through its binding to TLR7 it generates a cascade of reactions such as upregulation of cytotoxicity in NK cells, activation of macrophages to secrete cytokines, activation and migration of Langerhans cells from skin to lymph nodes and induction of proliferation and differentiation of T and B cells. Currently it is unknown if the topical application of imiquimod is able to exert, apart from a local, also a systemic immunomodulatory action. For this reason we tried to elucidate the effects of imiquimod on the immune system of patients with HSV and HPV infections at two levels. First we have measured the circulating cell populations in whole blood using flow cytometry and secondly we have determined the serum levels of IL-2, IL-4, IL-6, IL-10, TNF-α, IFN-α and IFN-γ with cytometric bead array. The results demonstrate that our hypothesis is correct and imiquimod could be an alternative and effective treatment of cutaneous HSV and HPV infections.

Submitted by Tatiana Silva (tsilva@icict.fiocruz.br) on 2013-02-08T13:31:12Z No. of bitstreams: 1 sabina_v_montero_ioc_bcm_0053_2011.pdf: 2783003 bytes, checksum: 58d0698eae0f2913066b128813d0d416 (MD5) / Made available in DSpace on 2013-02-08T13:31:12Z (GMT). No. of bitstreams: 1 sabina_v_montero_ioc_bcm_0053_2011.pdf: 2783003 bytes, checksum: 58d0698eae0f2913066b128813d0d416 (MD5) Previous issue date: 2011 / Fundação Oswaldo Cruz.Instituto Oswaldo Cruz. Rio de janeiro, RJ, Brasil / Pacientes infectados pelo HIV-1 apresentam aumentada permeabilidade intestinal, a qual permite a passagem para a circulação sanguínea de produtos microbianos, fenômeno conhecido por translocação microbiana. Dentre os produtos translocados são encontrados vários ligantes dos receptores do tipo Toll (TRL). A ativação de TLR desencadeia uma complexa cascata de sinalização, induz a síntese de diversas citocinas, e modula a função de células dendríticas (CDs), macrófagos e linfócitos, células-alvo da infecção pelo HIV-1. Estudos experimentais mostram que a ativação de TLRs influencia a replicação do HIV-1, como, por exemplo, a ativação de TLR-4 e TLR-3 resulta em diminuição da replicação viral. No entanto, os estudos relacionados à ativação de TLR-2 e HIV-1 são escassos. Assim, em nosso estudo, resolvemos analisar o efeito da ativação de TLR-2 sobre a replicação do HIV-1 em PBMCs e macrófagos primários humanos infectados in vitro. Para isto, PBMCs e macrófagos obtidos de doadores saudáveis foram infectados pelo HIV-1 e em seguida expostos ao Zymosaqn ou Pam3CSK4, ambos ligantes de TLR-2, e a replicação viral foi avaliada pela detecção da proteína viral p24 nos sobredanantes de cultura. Vimos que tanto o Zymosan quanto o Pam3CSK4 inibem de forma potente (até 90%) a replicação do isolado Ba-L (trópico para CCR5) de HIV-1 em PBMCs e macrófagos, assim como isolados primários trópicos para CCR5 e CXCR4. o tratamento das células com os ligantes de TLR-2 antes da infecção também induziu a queda da replicação viral. Ambos os ligantes de TLR-2 induziram aumento da produção das β-quimiocinas CCL3, CCL4 e CCL5 em macrófagos e PBMCs, e de IL-10 em macrófagos. A imuno-neutralização das β-quimiocinas diminuiu expressivamente o seu efeito inibitório sobre a replicação do HIV-1,. sugerindo que estas moléculas participam da inibição da replicação do HIV-1 resultante da ativação de TLR2. no entanto, a neutralização do receptor de IL-10 não produziu resultados semelhantes. A expressão dos receptores celulares CD4, CCR5 e CXCR4 não foi alterada quando macrófagos e PBMCs foram tratados com Pam3CSK4. observamos, ainda, que a proteína quinase R (PKR) é ativada por Pam3CSK4 tanto em macrófagos quanto em PBMCs. Estes resultados mostram que a ativação de TLR-2 resulta em uma potente inibição da replicação do HIV-1 em PBMCs e macrófagos, e sugerem que as β-quimiocinas estão envolvidas neste fenômeno. Nossos achados ressaltam o papel anti-HIV-1 resultante da ativação de TLR-2, e indicam que novos estudos devem ser realizados para esclarecer, com maior profundidade, os mecanismos envolvidos neste processo / Patients infected with HIV-1 exhibit increased intestinal permeability, which allows passage into the bloodstream of microbial products, a phenomenon known as microbial translocation. Among the products are found translocated several ligands of Toll-like receptors (TRL). The activation of TLR triggers a complex cascade of signaling, inducing synthesis of different cytokines, and modulates the function of dendritic cells (DCs), macrophages and lymphocytes, target cells from infection by HIV-1. Experimental studies have shown that activation of TLRs influences the replication of HIV-1, for example, activation of TLR-4, TLR-3 results in decreased viral replication. However, studies related to the activation of TLR-2 and HIV-1 are scarce. Thus, in our study, we decided to analyze the effect of the activation of TLR-2 on HIV-1 replication in PBMCs and human primary macrophages infected in vitro. For this purpose, PBMC and macrophages obtained from healthy donors were infected with HIV-1 and then exposed to Zymosaqn or Pam3CSK4, both from the TLR-2 ligands, and viral replication was assessed by the detection of viral protein p24 in culture sobredanantes. We have seen that both Zymosan as potently inhibit Pam3CSK4 (up to 90%) replication isolated Ba-L (CCR5 tropic) HIV-1 PBMC and macrophages, as well as primary isolates tropic CCR5 and CXCR4. treating the cells with the ligands of TLR-2 prior to infection also induced decrease in viral replication. Both ligands of TLR-2 induced increased production of β-chemokines CCL3, CCL4 and CCL5 in PBMC and macrophages, and IL-10 in macrophages. The immuno-neutralization of β-chemokine significantly reduced their inhibitory effect on the replication of HIV-1. suggesting that these molecules participate in inhibiting the replication of HIV-1 resulting from activation of TLR2. However, the neutralization of IL-10 did not produce similar results. The expression of cell receptors CD4, CCR5 and CXCR4 was not altered when macrophages and PBMCs were treated with Pam3CSK4. noted further that protein kinase R (PKR) is activated by Pam3CSK4 in both macrophages and in PBMCs. These results show that activation of TLR-2 results in a potent inhibition of HIV-1 replication in PBMC and macrophages, and suggest that β-chemokines are involved in this phenomenon. Our findings highlight the role of anti-HIV-1 resulting from the activation of TLR-2, and suggest that further studies should be conducted to clarify, in greater depth, the mechanisms involved in this process

Cardiac dysfunction is a major consequence that contributes to the high mortality of trauma-hemorrhage (TH) patients. Recent evidence suggests that innate immune and inflammatory responses mediated by Toll-like receptors (TLRs) play a critical role in the pathophysiologic mechanisms of acute organ dysfunction during TH. This study investigated the role of TLR4 in cardiac dysfunction following TH. Toll-like receptor 4-deficient (TLR4-/-, n = 7/group) and age-matched wild-type (WT, n = 8/group) mice were subjected to TH that was induced by soft tissue injury and blood withdrawal from the jugular vein to a mean arterial pressure of 35 ± 5 mmHg. Cardiac function and mean arterial pressure were measured with a Millar system before, during, and after blood withdrawal. Sham surgical-operated mice served as control (WT, n = 9/group; TLR4-/-, n = 10/group). Cardiac function in WT mice was significantly reduced following TH. However, cardiac function was well preserved in TLR4-/- mice. Administration of a TLR4 antagonist (3 mg/kg) to WT mice also significantly attenuated TH-induced cardiac dysfunction. Western blot showed that either TLR4-/- or TLR4 antagonist markedly attenuated TH-induced decreases in the levels of phosphorylated-Akt in myocardium. In addition, inhibition of TLR4 attenuated TH-induced myocardial nuclear factor κB-binding activity as well as lung myeloperoxidase activity and tumor necrosis factor α production. The data indicate that TLR4 plays a central role in TH-induced cardiac dysfunction. Toll-like receptor 4 deficiency or TLR4 inhibition attenuated cardiac dysfunction following TH, which may involve activation of the phosphoinositide 3-kinase/Akt signaling and decrease in nuclear factor κB-binding activity. Toll-like receptor 4 antagonism may be a new and novel approach for the treatment and management of cardiac dysfunction in TH patients.

Obesity-induced chronic inflammation plays a key role in the pathogenesis of insulin resistance and the metabolic syndrome. Proinflammatory cytokines can cause insulin resistance in adipose tissue, skeletal muscle and liver by inhibiting insulin signaling transduction. Interleukin-1 receptor-associated kinase-1 (IRAK-1) is a serine/threonine kinase functioning in Toll-like Receptor signaling pathways, and plays an important role in inflammation and immune response. In our studies, we demonstrated that IRAK-1 is involved with the negative regulation of PI3K-Akt dependent signaling pathway induced by insulin and TLR 2&4 agonists. Out data also indicate that IRAK-1 can interact with IRS-1 protein both in vivo and in vitro. The binding sites for the IRAK1-IRS1 biochemical interaction are IRS-1's PH domain and IRAK-1's proline-rich LWPPPP motif. Our studies also indicate that IRAK-1 is involved with the negative regulation of glycogen synthesis through inhibiting PI3K-Akt signaling pathway and thus releasing GSK3β's inhibitory effect on glycogen synthase. Moreover, our studies also suggest that IRAK-1 is involved in the activation of transcription factors CREB and ATF-1 by stimulating CREB-Ser133 and ATF-1 phosphorylation. CREB transcription factor family induces genes involved in cellular metabolism, gene transcription, cell cycle regulation, cell survival, as well as growth factor and cytokine genes. That may partially explain our finding that IRAK-1 may be also involved with cell proliferation and survival pathway. / Master of Science

L'interaction entre le système immunitaire et le métabolisme du fer est bien illustrée par l'anémie des maladies chroniques (ACD), qui est fréquemment rencontrée dans les infections chroniques, l'inflammation et le cancer. La majorité des modifications dans les paramètres du fer observées dans l’ACD tient compte des modifications de l’homéostasie du fer, avec la délocalisation du métal de la circulation et les sites de l'érythropoïèse au compartiment de stockage dans les macrophages. Les mécanismes de la réponse hyposidérémique impliquent des cytokines, notamment TNF-alpha et IL-6, qui régulent les niveaux de plusieurs gènes du métabolisme du fer, y compris les transporteurs de fer et de l'hepcidine, un régulateur négatif de l’absorption du fer, ce qui entraîne l'inhibition de l'exportation du fer à travers la ferroportine 1 (FPN1) au niveau de l'intestin et les macrophages. Des études antérieures ont montré que l'IL-6 induit l’expression d’hepcidine dans les hépatocytes, mais il y a très peu de données concernant la façon par laquelle l'hepcidine et la FPN1 sont régulées dans les macrophages. Récemment, nous avons constaté que l'induction de l'hepcidine dans le foie par le lipopolysaccharide (LPS) dépend de la voie de signalisation médiée par le récepteur Toll-like 4 (TLR4). Le but de ce travail est d’identifier les ligands des TLRs capables d'induire l'hepcidine dans les macrophages et de déterminer l’exigence des TLRs dans l’induction de l’hepcidine et le développement d’hyposidérémie. En plus, nous voulons étudier l’effet de l’inflammation causée par les ligands des TLRs sur le taux de fer sérique, la production des cytokines et l'expression de l’hepcidine et de la ferroportine. D’autre part nous voulons étudier l’effet du taux du fer sur la production d’IL-6 macrophagique en réponse à la stimulation par le TLR4. D'abord, pour identifier les ligands des TLRs capables d'induire l'hepcidine dans les macrophages, nous avons traité les macrophages RAW 264.7 et les macrophages péritonéaux de souris (MPMs) avec différents ligands TLRs et on a mesuré l’expression de l'hepcidine par qRT-PCR. Nous avons observé que Pam3CSK4 (Pam), un ligand de TLR2/1; LPS, un ligand de TLR-4 et FSL1 un ligand de TLR2/6 induisent l’expression de l'hepcidine dans les cellules RAW 264.7 et les MPMs, contrairement au polyinosinic: polycytidylic acid (Poly I: C), un ligand de TLR3. De plus, LPS était capable de réprimer l’expression de la ferroportine dans les cellules RAW 264.7. Afin de mieux définir la nécessité des TLRs pour assurer cette expression, nous avons utilisé les souris TLR-2 knock-out et on a établi que l'expression de l'hepcidine dans les macrophages par LPS, Pam ou FSL1 est dépendante du TLR2. En accord avec les expériences in vitro, les études effectuées in vivo ont montré que LPS réprime l’expression de la ferroportine, ainsi que PolyI:C n’est pas capable de stimuler l'expression d'hepcidine hépatique, par contre il était efficace pour déclencher une hyposidérémie. Ensuite, on voulait déterminer la voie de signalisation utilisée dans l’induction de l’hepcidine dans les macrophages. Comme il y deux voies majeures connues pour la signalisation des TLRs : une dépendante et l’autre indépendante de la protéine MyD88, on a étudié l’expression de l’hepcidine dans les MPMs isolés des souris MyD88-/- et nous avons constaté que l'absence de signalisation MyD88 abolit l'induction de l'hepcidine déclenchée par Pam, LPS et FSL1. D’autre part, la stimulation avec du LPS induisait in vivo la production d’IL-6 et de TNF-alpha, et la stimulation d’IL-6 était renforcée in vitro par la présence du fer. Ces observations indiquent que l’expression de HAMP (Hepcidin Antimicrobial Peptide) dans les macrophages peut être régulée par différents TLRs, ce qui suggère que la production d'hepcidine macrophagique fait partie d'une réponse immunitaire activées par les TLRs. / The interaction between the immune system and iron metabolism is well exemplified in the anemia of chronic disease (ACD), which is frequently encountered in chronic infections, inflammation and cancer. The major changes in iron parameters observed in ACD ultimately reflect modifications in iron trafficking, with relocation of the metal from both the circulation and sites of erythropoiesis to the storage compartment in macrophages. Mechanisms in the hypoferremic response involve cytokines, including TNF-alpha and IL-6. These pro-inflammatory cytokines regulate the levels of several iron metabolism genes, including iron transporters and hepcidin, a negative regulator of iron absorption, resulting in the inhibition of iron export by ferroportine 1 (FPN1) from the intestine and macrophages. Previous studies showed that IL-6 upregulates hepcidin in hepatocytes, but there are very few data regarding how hepcidin and FPN1 expression is regulated in macrophages. More recently, we found that hepcidin induction in the liver by lipopolysaccharide (LPS) is dependent on the signaling pathway mediated by toll-like receptor 4 (TLR4). The aim of this work is to identify TLR ligands able to induce hepcidin in macrophages and to determine the requirement for TLRs in hepcidin expression and the development of hypoferremia. In addition, we want to study the effect of inflammation induced by TLR ligands on serum iron levels, cytokine production, hepcidin and ferroportin expression. On the other hand we want to study the effect of iron levels on IL-6 production by macrophages in response to TLR4 stimulation. First, to identify TLR ligands capable of inducing hepcidin in macrophages, we treated Raw 264.7 macrophages and thioglycollate-stimulated mouse peritoneal macrophages (MPMs) with various TLR ligands and measured hepcidin and ferroportin expression by real-time RT-PCR. We observed that Pam3CSK4 (Pam), a TLR1/2 ligand; LPS, a TLR-4 ligand; and FSL1 a TLR6/2 ligand, but not polyinosinic: polycytidylic acid (poly I:C), a TLR3 ligand, upregulate hepcidin expression in both Raw 264.7 cells and MPMs. Furthermore, LPS was able to repress ferroportine expression in RAW 264.7 macrophages. To further define the requirement for the identified TLRs, we used TLR-2 knockout mice and established that upregulation of macrophage hepcidin expression by Pam or FSL1 is TLR2 dependent, respectively. In agreement with the in vitro experiments, when tested in vivo LPS repressed ferroportine expression and polyI:C failed to induce hepatic hepcidin expression but was effective in triggering hypoferremia. We next investigated whether MyD88, the predominant but not exclusive intracellular signal transduction pathway for TLR-4, is necessary for hepcidin induction in macrophages. Using MyD88 knockout mice, we found that the absence of MyD88 signaling abolishes hepcidin induction triggered by Pam, LPS and FSL1. On the other hand, stimulation with LPS induced in vivo the production of IL-6 and TNF-alpha, and IL-6 stimulation was enhanced in vitro by high amount of iron in macrophages.These observations indicate that HAMP (Hepcidin Antimicrobial Peptide) expression in macrophages can be regulated through multiple TLRs, suggesting that macrophage hepcidin production is part of an immune response activated by the TLRs.

A interação entre a imunidade inata e adaptativa acontece durante diversas fases da resposta imune. Os Toll-like receptors (TLRs) tem importante papel na ativação de macrófagos e portanto, no conjunto de moléculas secretadas por estas células. Pouco se sabe sobre o papel destas substâncias no processo de contração da população de células T ativadas (Activation-induced cell death - AICD). Portanto, o objetivo do presente trabalho foi avaliar se macrófagos estimulados com diferentes agonistas de TLRs poderiam produzir fatores solúveis com capacidade modulatória da morte por AICD. Primeiramente, demonstramos que tanto a linhagem macrofágica J774, quanto os macrófagos derivados de medula óssea (BMDMs) expressam todos os TLRs, com excessão do TLR11. Comprovamos que estas proteínas são funcionais, uma vez que o estímulo com agonistas de TLRs leva à ativação de NF-<font face=\"Symbol\">&#954B nestes macrófagos. Finalmente, mostramos que os sobrenadantes gerados pelos macrófagos são capazes de proteger as células DO11.10 da AICD, via a regulação negativa de FasL, parcialmente mediada por PGE2. / The interaction between innate and adaptative immunity occurs in several phases of the immune response. The Toll-like receptors (TLRs) have an important role in the activation of macrophages directly acting on the molecules secreted by these cells. Little is known about the role of these secreted molecules on the survival control of activated T lymphocytes (Activation-induced cell death - AICD). Therefore, the objective of the present work was to evaluate the effects of soluble factors produced by macrophages activated with several TLRs agonists, on the survival of T lymphocytes. First we sought the expression of TRLs on both bone marrow-derived and J774 macrophage cell line and we could see that both cells express all TLRs, except for TLR 11. The stimulation of both cells with TLRs agonists leads to the expression of NF-<font face=\"Symbol\">&#954B and the production of soluble factors that are able to protect DO11.10 T lymphocyte cell line from AICD, via down regulation of FasL partially mediated by PGE2.

Células tumorais desenvolvem diversas estratégias para escapar da identificação e eliminação pelo sistema imune. Dessa forma, a investigação dos mecanismos envolvidos na comunicação celular no microambiente tumoral e na desregulação local do sistema imune é crítica para uma melhor compreensão da progressão da doença e para o desenvolvimento de alternativas terapêuticas mais eficazes. Nós aqui demonstramos que SIGIRR/IL-1R8, um importante regulador negativo de receptores de Interleucina-1 (ILRs) e receptores do tipo Toll (TLRs), apresenta expressão aumentada em uma linhagem celular epitelial mamária transformada pela superexpressão do oncogene HER2 e em tumores primários de mama, e promove o crescimento tumoral e metástase através da modulação da inflamação associada ao câncer e da atenuação da resposta imune antitumoral. Observamos que IL-1R8 tem sua expressão correlacionada com HER2 em tecidos mamários e sua alta expressão é fator de pior prognóstico em câncer de mama de baixo grau. Notavelmente, níveis aumentados de IL-1R8 foram observados especialmente nos subtipos HER2+ e Luminais de tumores de mama, e sua expressão aumentada em células epiteliais de mama transformadas por HER2 diminui a ativação da via de NF-&#954;B e a expressão de diferentes citocinas pro-inflamatórias (IL-6, IL-8, TNF, CSF2, CSF3 e IFN-&#946;1). Meio condicionado de células transformadas por HER2, mas não de variantes celulares com o gene IL-1R8 silenciado, induz a polarização de macrófagos para o fenótipo M2 e inibe a ativação de células NK. Em um modelo murino transgênico de tumorigênese espontânea mediada por HER2, MMTV-neu, verificamos que a deficiência de IL-1R8 (IL-1R8-/-neu) retardou o aparecimento de tumores e reduziu a incidência, a carga tumoral e a disseminação metastática. Contudo, não foram observadas diferenças significativas no crescimento tumoral quando animais IL-1R8-/-neu receberam medula óssea de animais IL-1R8+/+, confirmando um papel importante da expressão de IL-1R8 em células não hematopoiéticas na tumorigênese da mama. Tumores IL-1R8+/+neu apresentaram maiores níveis de citocinas pró-inflamatórias como IL-1&#946; e VEGF, e menores níveis da citocina imunomodulatória IFN-&#947;. Além disso, tumores que expressavam IL-1R8 apresentaram menor infiltrado de células NK maduras, células dendríticas (DCs) e linfócitos T-CD8+ e um maior infiltrado de macrófagos M2 e linfócitos T-CD4+. Coletivamente, esses resultados indicam que a expressão de IL-1R8 em tumores de mama pode representar um novo mecanismo de escape da resposta imune e suportam IL-1R8 como potencial alvo terapêutico. / Tumor cells develop numerous strategies to fine-tune inflammation and avoid detection and eradication by the immune system. Identification of new players that regulate the cellular crosstalk within the tumor microenvironment and promote local immune dysregulation is critical to understand disease progression and to improve therapeutic strategies. Here, we demonstrate that SIGIRR/IL-1R8, a negative regulator of IL-1R and TLRs, is up-regulated in a HER2-transformed epithelial mammary cell line and in primary breast tumors and promotes tumor growth and metastasis by modulating cancer-related inflammation and impairing anti-tumor immunity. IL-1R8 expression is correlated with HER2 in mammary tissue, and higher tumor IL-1R8 expression is a poor prognostic factor in lower grade breast tumors. Notably, higher levels of IL-1R8 expression were observed in HER2+ and Luminal breast tumor subtypes and IL-1R8 up-regulation in HER2-transformed mammary epithelial cells inhibited NF-&#954;B activation and the expression of pro-inflammatory cytokines (IL-6, IL-8, TNF&#945;, CSF2, CSF3, IFN-&#946;1). Conditioned medium from HER2-transformed cells, but not from IL-1R8 knockdown variants, induced M2-macrophage polarization and inhibited natural-killer (NK) cell activation. IL-1R8 deficiency in a transgenic mouse model of breast tumorigenesis (MMTV-neu) significantly delayed tumor onset and reduced tumor incidence, burden and metastasis. No significant differences in tumor growth were observed when IL-1R8-/-neu mice were transplanted with bone marrow from IL-1R8+/+ animals, confirming an important role for IL-1R8 expression in non-hematopoietic cells during breast tumorigenesis. IL-1R8+/+neu mammary tumors presented higher levels of pro-inflammatory cytokines such as IL-1&#946; and VEGF, but lower levels of IFN-&#947;. Besides, a lower infiltrate of mature NK cells, dendritic cells (DCs) and CD8+ T cells but higher infiltrate of M2-macrophages and CD4+ T cells were present in IL-1R8 expressing tumors. Collectively, our results support IL-1R8 expression as a novel tumor immune escape mechanism in breast cancer and putative target for immunotherapy.