No description available.

Interleukin (IL)-1beta is a powerful pro-inflammatory cytokine with important roles in directing both innate and adaptive immunity. As a result, its production is tightly controlled, with the synthesis of an inactive form (pro-IL-1beta) and the requirement of a second signal. This induces the formation of the inflammasome, a macromolecular complex which mediates the maturation of IL-1beta into the bioactive cytokine. Given its significance, it is important to identify mechanisms of IL-1beta induction and modulation. Firstly, we describe serum amyloid A (SAA), an acute phase protein with immunomodulatory properties, as a novel inducer of IL-1beta. Using cells from genetically modified mice, the molecular mechanisms responsible were dissected, demonstrating the receptors TLR2 and NLRP3 as required for this effect. By instilling SAA into mice, we also show that SAA is able to induce IL-1beta production in vivo. Invariant natural killer T (iNKT) cells have also been shown to be important modulators of immunity, mediating both pro- and anti-inflammatory responses. iNKT cells are non-conventional T lymphocytes which recognise glycolipid in the context of CD1d, with the ability to interact with immature antigen presenting cells in an autoreactive manner. We link the regulatory ability of iNKT cells with IL-1beta production, showing that a low activation signal leads to the induction of an IL-13-dominated cytokine profile, as well as weak engagement of the CD40-CD40L pathway. We show for the first time that through these mechanisms, iNKT cells are able to dampen the secretion of IL-1beta upon subsequent stimulation of dendritic cells. We hypothesise that this effect of iNKT cells is important in controlling inflammatory responses in vivo, and demonstrate exacerbated IL-1beta production and inflammation during influenza virus infection of iNKT cell-deficient animals. This novel anti-inflammatory property of iNKT cells may be harnessed in the therapeutic intervention of inflammatory disorders.

L’inflammation fait partie des processus réactionnels de défense dont dispose l’organisme en réponse aux agressions, assurant l’intégrité de l’hôte. En réponse au dommage tissulaire, plusieurs médiateurs inflammatoires interviennent dans le processus de l’inflammation. Lors de ces dommages, des signaux de dangers provenant de cellules endommagées sont relâchés dans l’environnement tissulaire, pouvant causer des dommages cellulaires et tissulaires. Les macrophages, tout comme d’autres cellules, peuvent être activés par ces signaux de danger, menant à la sécrétion de molécules telles que des cytokines et des chimiokines pouvant modifier le microenvironnement tissulaire. Les insultes au tissu sain peuvent entrainer la mort cellulaire telle que l’apoptose. Les molécules pouvant être relâchées lors de celle-ci contribuent au microenvironnement, notamment de par l’influence de celles-ci sur le macrophage. Parmi ces médiateurs, nous avons identifié le Milk Fat Globule-Epidermal growth factor 8 (MFG-E8), un acteur important dans la résolution de l’inflammation, comme étant relâché spécifiquement par les cellules apoptotiques. Nous avons émis l’hypothèse que le microenvironnement apoptotique tissulaire, via la relâche de MFG-E8, module le phénotype du macrophage, modifiant le microenvironnement, la réponse inflammatoire ainsi que le devenir de l’insulte tissulaire. Nos objectifs sont 1) de caractériser ce microenvironnement apoptotique tissulaire et la cinétique de relâche du MFG-E8 par les cellules apoptotiques, 2) d’en évaluer son rôle dans la modulation du phénotype du macrophage ainsi que 3) d’en étudier, in vivo, son influence sur l’environnement inflammatoire et le devenir tissulaire. Dans le premier article présenté, nous avons démontré que les cellules endothéliales apoptotiques relâchent le MFG-E8 de façon Caspase-3 dépendante. La stimulation des macrophages par l’environnement conditionné par les cellules endothéliales apoptotiques mène à l’adoption d’un profil macrophagien davantage anti-inflammatoire et moindrement pro-inflammatoire. Ce phénotype est réduit par l’inhibition de la Caspase-3 et il dépend de la présence de MFG-E8. De plus, le potentiel du MFG-E8 à la reprogrammation du macrophage pro-inflammatoire a été démontré via un modèle expérimental de péritonite. Ce changement phénotypique médié par MFG-E8 implique une signalisation STAT3. Ayant démontré que les cellules épithéliales apoptotiques, à l’instar des cellules endothéliales apoptotiques, relâchent elles aussi de façon apoptose-dépendante le MFG-E8, nous avons étudié plus exhaustivement un modèle in vivo riche en apoptose épithéliale, l’obstruction urétérale unilatérale. Dans ce deuxième article présenté, nous rapportons l’implication bénéfique de MFG-E8 dans ce modèle de pathologie rénale obstructive. Nous avons constaté que la présence ou l’administration de MFG-E8 réduit le dommage tissulaire et la fibrose. La protection conférée par MFG-E8 est médiée via la modulation de l’activation de l’inflammasome. De plus, nos résultats illustrent l’importance du phénotype anti-inflammatoire du macrophage médié par le MFG-E8 dans la régulation négative de l’activation de l’inflammasome rénal et du dommage tissulaire. Cette thèse présente la première description de la relâche Caspase-3-dépendante de MFG-E8 par les cellules apoptotiques. Elle démontre également l’importance du MFG-E8 dans le microenvironnement apoptotique inflammatoire dans l’atténuation du phénotype pro-inflammatoire du macrophage. De plus, nous avons démontré son rôle protecteur dans des modèles in vivo de transplantation aortique et de réparation tissulaire, de même que dans un modèle de maladie rénale chronique où nous avons montré que cette protection conférée par MFG-E8 est médiée par la régulation négative de l’inflammasome tissulaire. Nos résultats suggèrent ainsi que le MFG-E8 pourrait être considéré comme un interrupteur inflammatoire et ainsi comme une cible potentielle dans la modulation de maladies inflammatoires. / Inflammation is an important component of the « response to injury » process, allowing host integrity. In response to injury, released inflammatory mediators from damaged cells play a crucial role in the modification of the inflammatory microenvironment, which can lead to more cellular and tissue damages. Macrophages can be activated by those danger signals, leading to a spectrum of cytokines and chemokines secretion and modulating the tissular microenvironment. Tissue injuries can lead to cell death such as apoptosis. Mediators released during apoptosis contribute to the nature of the microenvironment, by their influence on macrophage amongst others. We have identified that Milk Fat Globule-Epidermal growth factor 8 (MFG-E8), an important actor in inflammation resolution, is specifically released by apoptotic cells. We hypothesized that tissular apoptotic microenvironment, through MFG-E8 release, modulates macrophage phenotype, resulting in the modification of microenvironment, inflammatory response and tissu injury outcome. Thus, our objectives were to 1) characterize this tissular apoptotic microenvironment by studying MFG-E8 release kinetic by apoptotic cells, to 2) evaluate its role in macrophage phenotype modulation and to 3) study, in vivo, its influence on inflammatory environment and tissu damage outcome. In the first study, we demonstrated that MFG-E8 is released by apoptotic endothelial cells in a caspase-3-dependent manner. When macrophages were exposed to conditioned media from apoptotic endothelial cells, they adopt a high anti-inflammatory, low pro-inflammatory cytokine/chemokine secreting phenotype that is lost if apoptosis is inhibited or if MFG-E8 is absent from the media. Furthermore, MFG-E8 potential to anti-inflammatory macrophage reprogramming has been demonstrated in the experimental peritonitis model. This MFG-E8-mediated reprogramming of macrophages occurs through increased phosphorylation of STAT-3. As apoptotic endothelial cells, apoptotic epithelial cells also release MFG-E8 in an apoptotic-dependent manner. Thus, we investiguated more exhaustively an in vivo epithelial apoptosis rich model, the unilateral ureteral obstruction. In this second study, we report the positive impact of MFG-E8 in this renal obstructive model. MFG-E8 administration reduced kidney damage and fibrosis compared to the control, whereas its absence in MFG-E8 KO mice was associated with more severe disease. Moreover, we demonstrated that the protective role of MFG-E8 is mediated through inflammasome activation modulation in the kidney. Furthermore, our results showed the importance of the anti-inflammatory macrophage phenotype that results in decreased inflammasome activation, preventing severe tissue damage. This thesis presents the first description of apoptosis-dependent release of MFG-E8 by apoptotic cells. It also demonstrate the importance of MFG-E8 in inflammatory apoptotic microenvironment, leading to pro-inflammatory macrophage phenotype attenuation. Moreover, we demonstrated MFG-E8 protective role in an aortic transplantation and a tissue repair models, as well as in a chronic kidney disease model where we showed that this MFG-E8 confered protection is mediated by negative regulation of tissular inflammasome activation. These data provide valuable insight for identifying MFG-E8 as a novel target in the modulation of inflammatory diseases and could be considerate as an inflammatory switch.

Embora já tenha sido comprovada a ação adjuvante da SBA-15, pouco se sabe sobre o seu mecanismo molecular que leva a modulação positiva da resposta imunológica. Foi avaliada a ativação do inflamassoma NLRP3, sobre estímulos de SBA-15, em macrófagos de camundongos C57BL/6. Como parâmetro dessa ativação, foi analisada a produção de IL-1β por ELISA. A SBA-15 foi capaz de induzir a produção de IL-1β a níveis semelhantes quando comparado com um agonista de NLRP3 (Nano-SiO2), sugerindo a ativação do inflamassoma. Para avaliar o envolvimento da caspase-1, nos resultados obtidos com a SBA-15, os macrófagos foram estimulados com sílica na presença do inibidor de caspase-1, e como esperado, a produção de IL-1β foi restaurada para o seu nível basal. A ativação do inflamassoma, por estímulos da SBA-15, parece ser parcialmente dependente da fagocitose e da produção das espécies reativas do oxigênio. Além disso, foi visto que a SBA-15 não induz a produção de IL-6, confirmando que essa sílica está envolvida na via do inflamassoma e não em outras vias, como por exemplo, NF-κB. / Although it has already been proven adjuvant action of SBA-15, little is known about its molecular mechanism leading to positive modulation of the immune response. NLRP3 inflammasome activation was evaluated on SBA-15 stimulation in C57BL/6 mice macrophages. As this parameter activation, it analyzed the production of IL-1β by ELISA. The SBA-15 was able to induce the production of IL-1β at levels similar when compared to an agonist of NLRP3 (Nano-SiO2), suggesting the activation of the inflammasome. To assess the involvement of caspase-1, the results obtained with SBA-15, the macrophages were stimulated with silica in the presence of caspase-1 inhibitor, and as expected, IL-1β production was restored to its baseline level. Activation of the inflammasome, by stimuli of SBA-15, appears to be partly dependent on phagocytosis and production of reactive oxygen species. In addition, it was seen that the SBA-15 does not induce IL-6 production, confirming that silica is involved inflammasome the path of and not in other ways, eg, NF-κB.

O diabetes mellitus tipo 2 (DM2), uma doença que afeta milhões de pessoas em todo o mundo, é marcado pela presença de complicações micro e macrovasculares, as quais estão associadas à disfunção endotelial, inflamação e fibrose. A aldosterona, cujos níveis plasmáticos estão elevados em pacientes e modelos experimentais de DM2, aumenta a geração de espécies reativas de oxigênio (ERO) e a expressão de marcadores inflamatórios. As citocinas IL-1? e IL-18 são liberadas principalmente após ativação de plataformas moleculares denominadas inflamassomas, as quais incluem os receptores NLRP3. Recentemente, demonstramos que o receptor NLRP3 contribui para a disfunção vascular induzida pela aldosterona. Considerando a existência de evidências que a aldosterona, via receptor mineralocorticoide (MR) e NLRP3, induz a produção de mediadores inflamatórios e, consequentemente, ativação do inflamassoma, podendo assim contribuir para o processo inflamatório no diabetes, nós hipotetizamos que o bloqueio de receptores MR e NLRP3 previne a ativação do inflamassoma e reduz o desenvolvimento das alterações vasculares funcionais associadas ao DM2. Observamos que artérias mesentéricas de animais diabéticos apresentam aumento da expressão/ativação de caspase-1 e IL-11?, aumento dos níveis plasmáticos de IL-1?, aumento da atividade da caspase- 1 em macrófagos do lavado peritoneal e prejuízo no relaxamento dependente de endotélio, comparativamente a artérias do grupo controle. Os tratamentos com espironolactona (antagonista MR) e MCC950 (inibidor de receptor NLRP3) atenuam a disfunção vascular, reduzem a expressão e a atividade da caspase-1 e diminuem os níveis plasmáticos de IL-1?. Células de músculo liso vascular e macrófagos derivados da medula estimulados com aldosterona também apresentam aumento da expressão dos componentes do inflamassoma, o que poderia contribuir para as alterações observadas em animais diabéticos. Pacientes com DM2 apresentam correlação positiva entre os níveis de aldosterona e de IL-1? e/ou glicemia. Em conclusão, nosso estudo demonstra que a aldosterona induz disfunção vascular e processo inflamatório no diabetes tipo 2 através da ativação de MR e do inflamassoma NLRP3. / Type 2 diabetes mellitus (T2DM), a disease that affects millions of people around the world, is marked by the presence of micro and macrovascular complications, which are associated with endothelial dysfunction, inflammation and fibrosis. Aldosterone excess aggravates endothelial dysfunction in diabetes by promoting insulin resistance, fibrosis, oxidative stress and inflammation. Aldosterone activates the molecular platform inflammasome in cells of the immune system, an event that contributes to vascular dysfunction induced by the mineralocorticoid hormone. However, it is unclear whether activation of the inflammasome contributes to the effects of aldosterone in diabetes-associated vascular abnormalities. In the present study we tested the hypothesis that aldosterone induces vascular dysfunction in T2DM via activation of mineralocorticoid receptors (MR) and assembly of the NLRP3 inflammasome. To determine whether aldosterone activates the NLRP3 inflammasome and NLRP3 activation contributes to diabetes-associated vascular dysfunction, mesenteric arteries from control mice (db/m) and mice with type 2 diabetes (db/db), treated with vehicle, spironolactone (MR antagonist) or the NLRP3 antagonist MCC950, were used. Db/db mice exhibited increased vascular expression/activation of caspase-1 and IL-1?, increased plasma IL-1? levels, increased number of caspase-1-positive macrophages in the peritoneal lavage as well as reduced acetylcholine (ACh) vasodilation, compared to control db/m mice. Treatment of db/db mice with spironolactone and MCC950 reduced vascular caspase-1, decreased plasma IL-1? levels and partly restored ACh responses. Spironolactone treatment also reduced the number of caspase-1-positive-macrophages in db/db mice. Vascular smooth muscle cells and bone marrow-derived macrophages stimulated with aldosterone also exhibited increased expression of inflammatory components, which may contribute to diabetes-associated vascular changes. Patients with T2DM exhibited a correlation between aldosterone and IL-1? levels and/or glycemia. In conclusion, our study demonstrates that aldosterone induces vascular dysfunction and inflammatory process in type 2 diabetes through MR receptor activation and NLRP3 inflammation.

A inibição crônica do óxido nítrico com Nw-nitroargininemethylester (L-NAME), associado à sobrecarga de sal, leva a hipertensão grave, albuminúria, glomeruloesclerose, isquemia glomerular e fibrose intersticial, caracterizando um modelo de doença renal crônica (DRC). Achados anteriores deste laboratório e de outros sugerem que a ativação de pelo menos duas vias da imunidade inata, TLR4/NF-kB e NLRP3/IL-1beta, ocorre em vários modelos experimentais de DRC e que a progressão da lesão renal pode ser atenuada com a inibição destas vias. No presente estudo, investigamos se a ativação da imunidade inata, através da via TLR4/NF-kB ou NLRP3/IL-1beta, está envolvida na patogênese da lesão renal em outro modelo de DRC, o de inibição crônica do NO com sobrecarga de sal. Ratos Munich-Wistar machos adultos receberam sobrecarga de sal (2% Na+ na dieta e 0,5% Na+ na água do bebedouro) e L-NAME (32 mg/Kg/dia) dissolvido na salina do bebedouro (Grupo HS+N) ou tratados com alopurinol (Alo, 36 mg/Kg/dia, v.o), usado como inibidor de NLRP3 (grupo HS+N+Alo) ou tratados com ditiocarbamato de pirrolidina (PDTC, 60 mg/Kg/dia, v.o), um inibidor de NF-kB (Grupo HS+N+PDTC). Após 4 semanas, os ratos HS+N desenvolveram hipertensão arterial, albuminúria e lesão renal, juntamente com inflamação renal, estresse oxidativo e ativação de ambas as vias NLRP3/IL1-beta e TLR4/NF-kB. Alo reduziu o ácido úrico renal e inibiu a via NLRP3/IL-1beta. Esses efeitos foram associados à atenuação da hipertensão arterial, albuminúria e inflamação/fibrose intersticial, mas não à lesão glomerular. O PDTC diminuiu o ácido úrico renal e inibiu as vias NLRP3 e NF-kB, promovendo um efeito antiinflamatório e nefroprotetor mais eficiente que o Alo. As vias NLRP3/IL-1beta e TLR4/NF-kB atuam paralelamente para promover lesão/inflamação renal e devem ser simultaneamente inibidas para obter nefroproteção maior nesse modelo de DRC / Nitric oxide inhibition with Nk-nitroargininemethylester (L-NAME) along with salt overload leads to severe hypertension, albuminuria, glomerulosclerosis, glomerular ischemia and collapse, together with interstitial fibrosis, characterizing a model of chronic kidney disease (CKD). Previous findings of this laboratory and elsewhere suggest that activation of at least two pathways of innate immunity, TLR4/NF-kB and NLRP3 inflammasome/IL-1beta, occurs in several experimental models of CKD, and that progression of renal injury can be slowed with inhibition of these pathways. In the present study, we investigated whether activation of innate immunity, through either the TLR4/NFkB or NLRP3/IL-1beta pathway, is involved in the pathogenesis of renal injury in yet another CKD model, chronic NO inhibition with salt overload. Adult male Munich-Wistar rats receiving L-NAME in drinking water and salt overload (Group HS+N) were treated with Allopurinol (ALLO), used as an NLRP3 inhibitor (Group HS+N+ALLO), or PyrrolidineDithiocarbamate (PDTC) a NF-kB inhibitor (Group HS+N+PDTC). After 4 wks, HS+N rats developed hypertension, albuminuria and renal injury, along with renal inflammation, oxidative stress and activation of both the NLRP3/IL1-beta and TLR4/NF-kB pathways. ALLO lowered renal uric acid and inhibited the NLRP3 pathway. These effects were associated with amelioration of hypertension, albuminuria and interstitial inflammation/fibrosis, but not glomerular injury. PDTC lowered renal uric acid and inhibited both the NLRP3 and NF-kB pathways, promoting a more efficient anti-inflammatory and nephroprotective effect than ALLO. NLRP3/IL-1beta and TLR4/NF-kB act in parallel to promote renal injury/inflammation and must be simultaneously inhibited for best nephroprotection

Dermatofitoses são infecções fúngicas de natureza crônica cujo principal agente etiológico é Trichophyton rubrum. Apesar de sua alta ocorrência mundial, pouco se sabe sobre os mecanismos imunológicos envolvidos nestas infecções. Neste trabalho investigamos a participação de duas classes de receptores de imunidade inata (NLRs e CLRs) na resposta a T.rubrum e avaliamos o perfil proteômico de macrófagos quando estimulados com o fungo. Observamos que T.rubrum foi capaz de induzir a produção de IL-1β dependente do inflamassomo NLRP3 e destacamos o papel da sinalização de IL-1 na modulação da resposta de IL-17. Determinamos os CLRs dectina-1 e dectina-2 como receptores essenciais na produção de citocinas inflamatórias e para o controle da infecção experimental. Curiosamente, a IL-17 e os linfócitos T e B foram dispensáveis para a eliminação do fungo. Também identificamos a proteína CLEC1A como uma novo receptor para fungos, envolvido no reconhecimento de glicolipídeos de T.rubrum. Por fim, a análise proteômica de macrofagos revelou a vimentina e a plastina-2 como duas proteínas potencialmente envolvidas na relação patógeno-hospedeiro. / Dermatophytosis are chronic fungal infections whose main causative agent is Trichophyton rubrum. Despite its high incidence worldwide, the immunological mechanisms underlying these infections remain largely unknown. Here we investigated the involvement of two classes of innate immune receptors (NLRs and CLRs) in the reponse to T.rubrum and performed a proteomic profiling of macrophages upon T.rubrum stimulation. We observed that T.rubrum was able to drive NLRP3 inflammasome-derived IL-1β production and highlighted IL-1 signaling as an important component in the shaping of the IL-17 response. We defined the CLRs dectin-1 and dectin-2 as key receptors for the induction of inflammatory cytokines and for the infection control in the in vivo settings. Curiously, IL-17 cytokines and T and B lymphocytes were dispensable for fungal clearance. In addition, we uncovered CLEC1A as a new receptor in fungal sensing, involved in the recognition of T.rubrum glycolipids. Finally, the proteomic analysis revealed Vimentin and Plastin-2 as two proteins potentially involved in the host-pathogen interaction.

A hiperalgesia inflamatória é o processo pelo qual ocorre a sensibilização dos neurônios nociceptores aferentes primários por mediadores químicos inflamatórios, gerando assim uma diminuição do limiar nociceptivo e como consequência episódios de dor. Entre os principais mediadores envolvidos com a sensibilizacão das fibras nociceptivas periféricas está a prostaglandina E2 (PGE2), que é liberada como um produto final de uma cascata de mediadores inflamatórios. Dentro desta cascata de liberação hierárquica podemos destacar a interleucina -1? (IL)-1?, uma citocina importante na gênese da dor inflamatória, devido à sua capacidade de induzir a produção da enzima cicloxigenase-2 (COX-2), e consequentemente PGE2. O mecanismo de controle da produção da IL-1 ? envolvem dois passos intracelulares: a indução da expressão de uma forma protêica inativa (a pró-IL-1 ?) e a geração da forma biologicamente ativa (IL-1?) a partir da pró-IL-1 ?. Este último passo envolve a ação de uma cisteína-protease ativada em decorrência de um processo inflamatório, conhecida como Caspase-1, a qual cliva a pró-IL-1? em IL1?. Recentemente, nosso grupo demonstrou que a caspase-1 tem um papel importante na gênese da dor inflamatória, sendo crucial para a geração de IL-1? e consequentemente COX2/PGE2. Porém, não são conhecidos os mecanismos de ativação da caspase-1 na hiperalgesia inflamatória. Sabe-se que a ativação da Caspase-1 e clivagem da pro-IL-1? são dependentes de uma plataforma molecular intracelular denominada inflamassoma. Os principais inflamassomas ativadores de caspase-1 são formados pelas proteínas NLRP3, IPAF (NLRC4) e por sua molécula adaptadora ASC. O objetivo desse trabalho então foi avaliar a participação do inflamassoma na gênese da dor inflamatória. Nós identificamos que as moléculas IPAF e ASC, mas não o NLRP3, participa no desenvolvimento da hiperalgesia inflamatória mecânica e térmica induzida pela carragenina. Observou-se que estas moléculas são cruciais para a ativação da Caspase-1 e, consequentemente, para a produção da IL-1? ativa. Estes resultados evidenciam pela primeira vez um papel importante do inflamassoma no desenvolvimento da hiperalgesia inflamatória. / The inflammatory hyperalgesic is the process by which occurs the sensitization of nociceptors primary afferent neurons by inflammatory chemical mediators, that generating a decreased nociceptive threshold and result in episodes of pain. Among the main of nociceptive mediators involved with sensitization of peripheral nociceptive fibers are prostaglandin E2 (PGE2), which is released as a final product of a cascade of inflammatory mediators. Within this hierarchical cascade of release can highlight interleukin-1? (IL)-1?, a cytokine important in the genesis of inflammatory pain due to their ability to induce the production of the enzyme cyclooxygenase-2 (COX-2) and consequently PGE2. The control mechanism production of intracellular IL-1 ? involved two steps: induction of expression of a protein inactive form (pro-IL-1 ?) and the generation of the biologically active form from pro-IL-1 ? (IL-1?). This last step involves the action of a cysteine protease-activated due to an inflammatory process, known as Caspase-1, which cleaves pro-IL-1? to IL-1?. Recently our group has demonstrated that caspase-1 plays an important role in the genesis of inflammatory pain, crucial for the generation of IL-1? and consequently COX2/PGE2. However, there aren\'t known mechanisms of activation of caspase-1 in inflammatory hyperalgesic. It is known that the activation of Caspase-1 cleavage and pro-IL-1? are dependent on an intracellular molecular platform called inflammassome. The main inflammassome activators of caspase-1 proteins are formed by NLRP3, IPAF (NLRC4) and its adapter molecule ASC. The aim of this study was to evaluate the inflammassome participation in the genesis of inflammatory pain. We have identified molecules IPAF and ASC, but not NLRP3, is participate in the development of mechanical and thermal inflammatory hyperalgesic induced by carrageenan. It was observed that these molecules are crucial for the activation of Caspase-1 and thus for the production of active IL-1?. These results demonstrate for the first time an important role of the inflammassome in the development of inflammatory hyperalgesic.

A hiperalgesia inflamatória é o processo pelo qual ocorre a sensibilização dos neurônios nociceptores aferentes primários por mediadores químicos inflamatórios, gerando assim uma diminuição do limiar nociceptivo e como consequência episódios de dor. Entre os principais mediadores envolvidos com a sensibilizacão das fibras nociceptivas periféricas está a prostaglandina E2 (PGE2), que é liberada como um produto final de uma cascata de mediadores inflamatórios. Dentro desta cascata de liberação hierárquica podemos destacar a interleucina -1? (IL)-1?, uma citocina importante na gênese da dor inflamatória, devido à sua capacidade de induzir a produção da enzima cicloxigenase-2 (COX-2), e consequentemente PGE2. O mecanismo de controle da produção da IL-1 ? envolvem dois passos intracelulares: a indução da expressão de uma forma protêica inativa (a pró-IL-1 ?) e a geração da forma biologicamente ativa (IL-1?) a partir da pró-IL-1 ?. Este último passo envolve a ação de uma cisteína-protease ativada em decorrência de um processo inflamatório, conhecida como Caspase-1, a qual cliva a pró-IL-1? em IL1?. Recentemente, nosso grupo demonstrou que a caspase-1 tem um papel importante na gênese da dor inflamatória, sendo crucial para a geração de IL-1? e consequentemente COX2/PGE2. Porém, não são conhecidos os mecanismos de ativação da caspase-1 na hiperalgesia inflamatória. Sabe-se que a ativação da Caspase-1 e clivagem da pro-IL-1? são dependentes de uma plataforma molecular intracelular denominada inflamassoma. Os principais inflamassomas ativadores de caspase-1 são formados pelas proteínas NLRP3, IPAF (NLRC4) e por sua molécula adaptadora ASC. O objetivo desse trabalho então foi avaliar a participação do inflamassoma na gênese da dor inflamatória. Nós identificamos que as moléculas IPAF e ASC, mas não o NLRP3, participa no desenvolvimento da hiperalgesia inflamatória mecânica e térmica induzida pela carragenina. Observou-se que estas moléculas são cruciais para a ativação da Caspase-1 e, consequentemente, para a produção da IL-1? ativa. Estes resultados evidenciam pela primeira vez um papel importante do inflamassoma no desenvolvimento da hiperalgesia inflamatória. / The inflammatory hyperalgesic is the process by which occurs the sensitization of nociceptors primary afferent neurons by inflammatory chemical mediators, that generating a decreased nociceptive threshold and result in episodes of pain. Among the main of nociceptive mediators involved with sensitization of peripheral nociceptive fibers are prostaglandin E2 (PGE2), which is released as a final product of a cascade of inflammatory mediators. Within this hierarchical cascade of release can highlight interleukin-1? (IL)-1?, a cytokine important in the genesis of inflammatory pain due to their ability to induce the production of the enzyme cyclooxygenase-2 (COX-2) and consequently PGE2. The control mechanism production of intracellular IL-1 ? involved two steps: induction of expression of a protein inactive form (pro-IL-1 ?) and the generation of the biologically active form from pro-IL-1 ? (IL-1?). This last step involves the action of a cysteine protease-activated due to an inflammatory process, known as Caspase-1, which cleaves pro-IL-1? to IL-1?. Recently our group has demonstrated that caspase-1 plays an important role in the genesis of inflammatory pain, crucial for the generation of IL-1? and consequently COX2/PGE2. However, there aren\'t known mechanisms of activation of caspase-1 in inflammatory hyperalgesic. It is known that the activation of Caspase-1 cleavage and pro-IL-1? are dependent on an intracellular molecular platform called inflammassome. The main inflammassome activators of caspase-1 proteins are formed by NLRP3, IPAF (NLRC4) and its adapter molecule ASC. The aim of this study was to evaluate the inflammassome participation in the genesis of inflammatory pain. We have identified molecules IPAF and ASC, but not NLRP3, is participate in the development of mechanical and thermal inflammatory hyperalgesic induced by carrageenan. It was observed that these molecules are crucial for the activation of Caspase-1 and thus for the production of active IL-1?. These results demonstrate for the first time an important role of the inflammassome in the development of inflammatory hyperalgesic.

The inflammasome complex is a multiprotein complex that may play a role in the pathogenesis of inflammatory bowel disease (IBD) by secreting the inflammatory cytokines interleukin (IL)-1β and IL-18, and inducing pyroptosis, as a response to signals through several inflammasome sensors. This study looked at the expression of several inflammasome components in the ileum and colon of patients suffering from IBD. The inflammasome sensors NLRP1, NLRP3, AIM2 and pyrin were upregulated in whole intestinal tissue of IBD patients, particularly in the colon. NLRP6 expression was increased in the colon of Crohn's disease patients, but not ulcerative colitis patients relative to colon of controls, and was reduced in the ileum of Crohn's disease patients compared to control ileum. Expression of caspase-1 and IL-1β, but not IL-18, were also increased in ileum and colon tissue from Crohn's patients. To identify the cell type where inflammasome expression was altered in Crohn’s disease, transcription of inflammasome subunits in intestinal tissue enriched for epithelial cells or lamina propria (LP) cells was analysed. These analyses indicated that LP cells have greater expression of the inflammasome sensors NLRP1, NLRP3, AIM2 and pyrin relative to epithelial cells, both during disease and in control tissue. Moreover, LP cells from Crohn’s patients have higher expression level of NLRP1, AIM2 and pyrin than LP cells from controls. In contrast the inflammasome sensor NLRP6 was more highly expressed by epithelial cells relative to LP cells in general, and NLRP6 expression in LP cells from IBD patients was lower than that observed in LP cells from controls. The observed differential expression of inflammasome components in controls versus IBD intestine and in different cellular fractions of intestinal tissue highlight the importance of understanding the role of the inflammasome in IBD and hints at the possibility of targeting the inflammasome pathway as a future treatment strategy.