Envenenamentos por serpentes do gênero Bothrops provocam reações sistêmicas e locais como coagulopatias, hemorragias, reação inflamatória, dor e mionecrose. Proteínas secretadas ricas em cisteínas (CRISPs) estão presentes nas peçonhas de serpentes e estão amplamente distribuídas entre mamíferos, répteis e anfíbios. Estão envolvidas em algumas reações biológicas, porém muitas funções ainda são desconhecidas. O presente trabalho objetivou o isolamento, a caracterização bioquímica/estrutural, enzimática e funcional, a avaliação do potencial inflamatório e avaliação da atividade sobre o sistema complemento de uma CRISP isolada da peçonha de Bothrops jararaca. A CRISP denominada BJ-CRP, foi isolada da peçonha de Bothrops jararaca através da combinação de três etapas cromatográficas: exclusão molecular em Sephacryl S-200, cromatografia de troca aniônica em coluna Source 15Q e cromatografia de fase reversa em coluna C18. O grau de homogeneidade foi determinado e confirmado por eletroforese SDS-PAGE, que mostrou uma banda única de 25,19 kDa, e por MALDI-TOF/TOF que apresentou a massa molecular de 24,6 kDa. A sequência N-terminal e a análise dos peptídeos trípticos por MALDI TOF/TOF demonstrou a presença de 100 resíduos de aminoácidos, os quais apresentaram até 96% de similaridade com sequências de outras CRISPs já descritas, porém de outros gêneros e espécies de serpentes, pois ainda não há CRISPs isoladas do gênero Bothrops. A BJ-CRP não possui atividade proteolítica sobre a azocaseína, o fibrinogênio e a fibrina. Também não apresentou atividade coagulante e hemorrágica, e não demonstrou atividade quando testada na concentração de 1?M em 13 diferentes canais para potássio dependentes de voltagem. Por outro lado, esta toxina foi capaz de induzir um processo inflamatório agudo (tempos de 1 e 4 horas), observado pelo recrutamento de neutrófilos e aumento da citocina pró-inflamatória IL-6 na cavidade peritoneal de camundongos. Ensaios realizados com a BJ-CRP e a peçonha de Bothrops jararaca mostraram modulação na atividade hemolítica promovida pela via clássica do sistema complemento. A BJ-CRP também promoveu ação direta sobre alguns componentes isolados do sistema complemento, como C3 e C4, conforme avaliado por SDS-PAGE e Western blot. O presente trabalho descreve a purificação da BJ-CRP, a primeira CRISP isolada da peçonha da serpente do gênero Bothrops. Os resultados obtidos são promissores e abrem perspectivas para o melhor entendimento desta classe de proteínas, e para a compreensão do mecanismo de ação desta classe de toxinas na resposta inflamatória induzida pelo envenenamento botrópico. / Envenomation by snakes from Bothrops genus is characterized by systemic and local effects such as coagulopathies, bleeding disorders, inflammation, pain and myonecrosis.The cysteine rich secretory proteins (CRISPs) are present in snake venoms and are widely distributed mammals, reptiles and amphibians. They are involved in certain biological activities, however many of their functions are still unknown. The aim of the present study was to isolate a CRISP from Bothrops jararaca and to biochemically/functionally characterize it by evaluating its involvement on inflammatory responses and on the complement system. The CRISP named BJ-CRP was isolated from Bothrops jararaca crude venom through the combination of three chromatographic steps: molecular exclusion on Sephacryl S-200 column, anion exchange chromatography on Source 15Q and reverse phase chromatography using C18 column. A high purity degree was obtained as confirmed by SDSPAGE, showing a single band of 25.19 kDa, and by MALDI-TOF/MS showing a molecular mass of 24.6 kDa. The N-terminal sequence and analysis of tryptic peptides by MALDI TOF/ MS resulted in the determination of 100 amino acid residues, which had up to 96% similarity to sequences from other snake venom CRISPs that were previously described, but from other genus and snake species. The BJ-CRP did not have proteolytic activity on azocasein, fibrinogen or fibrin. It did not show coagulant or hemorrhagic activity, and also did not show activity on 13 different voltage dependent potassium channels when tested at a concentration of 1?M. Moreover, this toxin was able to induce an acute inflammatory response (1 and 4 hours after injection), observed by the recruitment of neutrophils and increase of interleukin-6 into the peritoneal cavity of mice. BJ-CRP and B. jararaca crude venom were capable of modulating the hemolytic activity promoted by the classical pathway of the complement system, and BJ-CRP also showed direct action on some complement system components, such as C3 and C4 as evaluated by SDS-PAGE and Western blot. The present work describes the purification of BJ-CRP, the first CRISP isolated from a Bothrops snake venom. The results obtained showed to be promising and open up prospects in order to better understand the involvement of this class of toxins in the inflammatory response induced by Bothrops envenomation.

Diferentes mecanismos têm sido mostrados por estar envolvidos na evasão à morte mediada por complemento. Neste estudo, demonstramos que a aquisição do FH pela Leptospira é crucial para a sobrevivência das bactérias no soro e que estas espiroquetas interagem com FH, FHL-1, FHR-1 e C4BP. Nós também demonstramos que a ligação à estes reguladores é mediada pelas proteínas leptospiral immunoglobulin-like (Lig). FH se liga as proteínas Lig via short consensus repeat (SCR) principalmente pelos domínios 5 e 20. Ensaios de competição sugerem que FH e C4BP têm sítios de ligação diferentes nas proteínas Lig. Além disso, FH e C4BP ligados nas proteínas Lig mantêm a atividade de cofator, mediando a degradação de C3b e C4b pelo FI. Nós demonstramos que a aquisição de FH e C4BP pela L. biflexa transgênica para LigA e LigB exercem um papel de proteção na sobrevida destas bactérias. Análise por citometria de fluxo também confirmaram a capacidade das leptospiras transgênicas para controlar a deposição de C3, C4 e MAC. As proteínas Lig também foram capazes de ligar plasminogênio, o qual foi ativado em plasmina e esta enzima foi capaz de degradar fibrinogénio, C3b e C5. Estas clivagens inativam C3b e C5, evitando a progressão da cascata, e bloqueando as três vias de complemento. / Different mechanisms have been shown to be involved in evasion of complement-mediated killing. In this study, we demonstrate that acquisition of FH on the Leptospira surface is crucial for bacterial survival in the serum and that these spirochetes interact with FH, FHL-1, FHR-1 and C4BP. We also demonstrate that binding to these regulators is mediated by leptospiral immunoglobulin-like (Lig) proteins. FH binds to Lig proteins via short consensus repeat (SCR) domains 5 and 20. Competition assays suggest that FH and C4BP have distinct binding sites on Lig proteins. Moreover, FH and C4BP bound to immobilized Ligs display cofactor activity, mediating C3b and C4b degradation by FI. We demonstrated that acquisition of FH and C4BP by the LigA and LigB transformed L. biflexa have the protective role, being crucial by bacterial survival. Analysis by Cytometer fluid also confirmed the ability of L. biflexa expressing LigA and LiB to controller the deposition of C3, C4 and MAC. Lig proteins were able to bind plasminogen, which was activated to plasmin and this enzyme was able to degrade the fibrinogen, C3b and C5. These cleavages inactivate C3b and C5, preventing progression of the complement cascade and blocking the three complement pathways.

O veneno de serpentes do gênero Bothrops (responsáveis por 80% dos envenenamentos no Brasil) é composto por metalo e serinoproteases, disintegrinas, fosfolipases, entre outros, e pode causar edema, hemorragia, necrose, e manifestações sistêmicas, como coagulação intravascular, choque, falência renal e hemorragia. O veneno da B. pirajai ativa o sistema complemento (C), sugerindo uma contribuição para o agravamento dos sintomas. Considerando a importância do C no processo inflamatório e o papel das metaloproteinases nos envenenamentos, verificou-se que o tratamento do sangue total humano (onde células e mediadores plasmáticos interagem entre si) com ou sem a compstatina (inibidor de C3 do C), e com a metaloproteinase de classe PI do veneno de B. pirajai, levou a diferenças bastante significativas na expressão dos marcadores analisados nos leucócitos, na geração de anafilatoxinas e TCC, e na quantificação de citocinas e quimiocinas no plasma, sugerindo que a inibição do C reduz o processo inflamatório, podendo ser uma terapia efetiva para envenenamentos botrópicos. / The snake venom of Bothrops genus (responsible for 80% of envenomation in Brazil) is composed by metallo and serine proteases, disintegrins, phospholipase, among others, and can cause edema, hemorrhage, necrosis, and systemic manifestations, such as intravascular coagulation, shock, renal failure and systemic hemorrhage. The venom of B. pirajai is able to activate the complement system (C), suggesting a contribution to the worsening of symptoms. Considering the importance of C in the inflammatory process and the role of metalloproteinases in envenomation, it was found that treatment of human whole blood (where cells and plasma mediators interact) with or without compstatin (C3 inhibitor), and with a class PI metalloproteinase from B. pirajai\'s venom led to highly significant differences in the expression of the markers analyzed in leukocytes, in generation of anaphylatoxins and TCC, and quantification of cytokines and chemokines in plasma, suggesting that inhibition of C reduces the inflammatory process and may be an effective therapy for bothropic envenomations.

Na Martinica, os envenenamentos por Bothrops lanceolatus apresentam um quadro clínico trombótico, acompanhado de inflamação local extensa, envolvendo edema, dor e hemorragia limitada. Neste estudo foi mostrado que vários componentes do veneno compartilham similaridades antigênicas com venenos de espécies da América do Sul. O veneno de B. lanceolatus é citotóxico para queratinócitos e células endoteliais, induzindo a produção de citocinas e quimiocinas pro-inflamatórias pelas células. O veneno de B. lanceolatus ativa a cascata do complemento, liberando anafilatoxinas, assim como o complexo terminal do complemento. Ele apresenta uma ação proteolítica sobre os componentes purificados C3, C4, C5, e o inibidor de C1, C1-INH. O veneno também desequilibra o balanço de expressão dos reguladores do complemento na membrana das células endoteliais. Estes dados demonstram que o veneno de B. lanceolatus exibe uma potente ação proinflamatória, pela ativação do sistema complemento e pela sua toxicidade em células endoteliais. / In Martinique envenomations by Bothrops lanceolatus are characterized by a systemic thrombotic syndrome and important local inflammation, involving oedema and pain, but limited haemorrhage. In this study, we show that several components of B. lanceolatus venom share antigenic similarities with South American Bothrops species. Still, B. lanceolatus venom proteases present substrate specificity. The venom is cytotoxic for keratinocytes and endothelial vascular cells, inducing the production of pro-inflammatory cytokines and chemokines. B. lanceolatus venom activates the complement cascade, releasing anaphylatoxins and the terminal complement complex. It also shows a direct proteolytic activity upon the purified complement proteins C3, C4, C5, and the inhibitor of C1, C1-INH. B. lanceolatus venom modified the balance of complement regulators on endothelial cells membrane. In conclusion, B. lanceolatus venom displays important pro-inflammatory properties, as it activates the complement cascade and impacts endothelial cells.

Em trabalhos anteriores o nosso grupo mostrou que a vacina celular pertussis (wP) apresenta atividade adjuvante quando combinada a proteína A da superfície de Streptococcus pneumoniae (pneumococo), PspA, A formulação PspA5-wP induz altos níveis de anticorpos e proteção em camundongos após desafio com pneumococo. Neste trabalho foram avaliados os mecanismos da ação adjuvante e os componentes de B. pertussis responsáveis por este efeito. A imunização de camundongos com PspA em combinação a mutantes de B. pertussis ou componentes desta bactéria purificados mostrou que a presença da toxina pertussis (PT) capaz é essencial para induzir altos níveis de anticorpos anti-PspA e proteção significativa contra o desafio letal com pneumococo. Este efeito não foi dependente da atividade enzimática. Anticorpos anti-PspA e as proteínas do sistema complemento foram essenciais para a proteção conferida por PspA-wP. As vacinas celulares BCG e DTP combinadas a PspA, também apresentaram atividade adjuvante, induzindo anticorpos anti-PspA e proteção contra o desafio invasivo por pneumococo. / Previously our group showed that the pneumococcal surface protein A from Streptococcus pneumoniae (pneumococcus), PspA, when combined with cellular pertussis vaccine (wP) as adjuvant, induce high levels of antibodies and mice protection on pneumococcal challenge. In this work were used mutants and purified components derived from B. pertussis for investigate the components responsible for this adjuvant effect, through of mice immunizations in combination with the PspA5 (Clade 5 PspA) antigen. Pertussis toxin (PT) was able to inducing the higher levels of PspA5 specific antibodies and significative protection against the pneumococcal lethal challenge, independently of its enzymatic effect. Was observed that in the protection conferred by the PspA5-wP formulation thus as the anti-PspA5 antibodies, the complements proteins are essentials. Lastly, prime-boost experiments showed that the cellular vaccines BCG and DTP when combined to PspA5, induced high levels of anti-PspA5 antibodies and protection against invasive challenge with pneumococcus.

Tendo em vista a ocorrência de alterações no sistema imune relacionadas ao hipertireoidismo e à participação do sistema complemento (SC) em processos imunológicos, torna-se importante investigar se os hormônios tireoidianos teriam algum efeito sobre o SC. O SC é composto de uma série de proteínas séricas e de membrana que estão envolvidas em processos da resposta imune. Considerando que os hormônios tireoidianos estão envolvidos em uma série de processos biológicos, e que tanto o hipo- quanto hipertireoidismo podem acarretar alterações importantes nestes processos, os objetivos deste trabalho foram estudar o impacto de níveis séricos elevados de hormônios tireoidianos sobre a atividade do sistema complemento e produção de anticorpos. Foram utilizados ratos machos wistar para o modelo experimental de hipertireoidismo, investigando-se a atividade lítica das vias clássica/lectina e alternativa através de ensaios hemolíticos; os níveis séricos de fator B da via alternativa através do emprego de reagente deficiente de fator B; e a produção de anticorpos anti-hemácia de carneiro (SRBC) empregando ELISA (enzyme linked immunosorbent assay) e ensaios de plaque forming cell (PFC). O hipertireoidismo induzido não resultou em alterações da atividade lítica das vias clássica/lectina. Entretanto, a elevação dos níveis séricos de hormônios tireoidianos provocou uma redução da atividade lítica de via alternativa, de forma significante em doses de 1, 5, 50 e 100g de levotiroxina/200g de peso animal após 14 dias de tratamento, e com dose a partir de 0,15g de triiodotironina/200g de peso animal, após 7 e 12 dias de tratamento. Os níveis séricos funcionais de fator B foram reduzidos nestas condições. Além disso, ocorre redução da resposta de produção de anticorpos em ratos tratados com T3 e imunizados com SRBC. Estes resultados mostram que níveis elevados de hormônio tireoideano reduzem a capacidade funcional da via alternativa do SC , avaliada pelo desencadeamento da lise em decorrência da interação com hemácias de coelho. Esta redução poderia levar a uma menor geração de fragmentos com atividade nos processos de seqüestro e apresentação do antígeno e interação com as células envolvidas na resposta imune, resultando em títulos menores de anticorpos produzidos. Estudos adicionais são necessários para avaliar estas possibilidades. As observações deste estudo podem auxiliar para o melhor entendimento do impacto biológico das disfunções hormonais sobre a atividade do sistema complemento. / Considering the alterations of the immune system that occur in the hyperthyroidism, and the involvement of the complement system (CS) in immune processes, this work aimed to investigate the effect of high levels of thyroid hormones on the CS and on the antibody production. The CS comprehends a group of serum and membrane proteins which activation leads to the generation of protein fragments or complexes with important biologic functions, such as participation in events of the immune response. Wistar adult male rats treated with thyroid hormones were used as experimental model of hyperthyroidism, to evaluate the lytic activity of classical/lectin and alternative pathways of the CS through hemolytic assays; the serum levels of factor B employing serum deficient of this component (RB); and the production of anti-sheep red blood cells (SRBC) antibodies through enzyme linked immunosorbent (ELISA) and plaque forming cell (PFC) assays. Classic and lectin pathways activity was not affected in the hyperthyroidism. However in this condition the alternative pathway activity was significantly reduced at doses of 1; 5; 50 and 100 g of thyroxine (T4) /200g of animal weight/day after 14 days of treatment, or crescent doses starting from 0,15 g of triiodothyronine (T3) for periods of 7 and 12 days of treatment. The serum levels of factor B were also reduced in these conditions. In addition, there was a reduction of the antibody response in rats treated with T3 and immunized with SRBC. These results show that the functional capacity of alternative pathway is decreased in consequence of high levels of thyroid hormones as evaluated by its lytic potency triggered by the rabbit erythrocytes. This could them lead to a reduced generation of complement fragments active in antigen sequestering and presentation, and on the interaction of cells in the immune response decreasing the antibody production. Additional studies are required to evaluate these possibilities.

Durante o ciclo menstrual, o endométrio se torna receptivo à chegada do \"futuro embrião\". Estes eventos são regulados pela liberação de progesterona durante a fase secretória do ciclo, que aumenta a secreção do componente C3 do Sistema Complemento (SC). Neste período, também foi observado o aumento fisiológico da expressão de algumas proteínas reguladoras do SC (CRPs) como: C1Inh, C4bp, DAF, CD59 e clusterina, oque sugere uma forte regulação da atividade deste sistema, favorável à implantação e ao desenvolvimento embrionário. Modificações na expressão destas proteínas poderiam resultar em aborto espontâneo recorrente (AER).Neste trabalho estudou-se a expressão endometrial de DAF e CD59 noendométrio de pacientes com AER, durante a fase secretória do ciclo. Adicionalmente, verificou-se a ativação do SC através da presença do neoantígeno de C9 neste mesmo material. A casuística foi composta de nove mulheres férteis normais (Grupo Controle) e doze mulheres com AER (Grupo Aborto), todas analisadas durante a fase secretória do ciclo. A técnica utilizada para detecção destas proteínas foi a imunohistoquímica. O neoantígeno deC9 não foi detectado em nenhum dos grupos, tanto nas glândulas quanto no estroma endometrial. DAF e CD59 foram detectados tanto no Grupo Controle quanto no Grupo Aborto.Houve expressão nitidamente mais acentuada de ambas as CRPs, DAF e CD59, durante a fase secretória intermediária do Grupo Aborto, embora sem diferença estatística. Houve expressão para DAF e CD59 no estroma endometrial de ambos os grupos. Assim, os resultados deste trabalho apontam para a ausência do neoantígeno de C9 no endométrio humano normal e no endométrio humano de patologias como o AER. As CRPs, DAF e CD59, se mostraram presentes tanto no endométrio humano normal quanto no endométrio humano patológico por AER, com destaque para o aumento da expressão de DAF e CD59 na sub-fase intermediária secretória do ciclo menstrual, período crítico para a implantação, sugerindo que alguma alteração neste período possa resultar na posterior perda gestacional. / In the cycle menstrual, the endometrium becomes ready to the arrived of embryo future. These events are controlled by mechanisms like, liberation of progesterone during the secretory phase of cycle, that increases the secretion of C3 component of Complement System (CS). In this period, it was also observed the physiologic increase of the expressionof some CS regulatory proteins (CRPs) like: C1Inh, C4bp, DAF, CD59 and clusterin, a fact suggesting strong regulation of the activity this system. Changes in this regulation can be harmful to implantation and to embryonary development, causing recurrent spontaneous abortion (RSA). To goal of the present study is to evaluate the endometrial expression of the Membrane Complex Atack (MAC) of CS, representing by neoantígen C9, in the normal and patologic human endometrium with RSA during the secretory phase of the menstrual cycle and of the CRPs, DAF e CD59, in the patologic human endometrium with RSA during the secretory phase, contributing to better understanding of the CS regulation in the endometrium in no physiologic conditions. The study group consisted of twelve endometrial biopsy, during the secretory phase of the menstrual cycle, of women with RSA of no apparent cause, compared to a control group of nine endometrial biopsy, in the same phase, of normal fertile women evaluated to endometrial expression of the neoantígen C9, DAF e CD59 by the immunochemistry technique. Neoantigen C9 was not detected in any group, in the secretory phase of the menstrual cycle in the endometrial glandular epithelium and stromal cells. DAF e CD59 were expressed in both groups during the secretory phase. DAF e CD59 were detected more intensely during the intermediate secretory phase of the Abortion Group when compared to the Control Group. Meanwhile, it not detected any significance difference. There was expression of DAF e CD59 in the stromal cells to the both groups. In summary, we data show that neoantígeno de C9 isn\'t expressed in the normal and patologic human endometrium, and the CRPs, DAF e CD59, are expressed in the normal and patologic human endometrium, predominating in the intermediary secretory phase of the cycle compared to the controls suggesting that some changes in the implantation period can result in the future gestational loss.

Le système du complément est une cascade de défense immunitaire complexe et étroitement régulée, conduisant à des dommages tissulaires lorsqu’il est suractivé. L’hème, un motif moléculaire de danger dérivant de l’hémolyse, est capable d’activer le complément dans le sérum et à la surface des cellules endothéliales (CE) in vitro, suggérant un rationel pour examiner l’impact de l’activation du complément dans les maladies hémolytiques. L’objectif de ce projet était d’étudier si et comment l’hémolyse intravasculaire active le complément in vivo, et de comprendre les mécanismes sous-jacent conduisant à l’acquisition d’un phénotype activateur du complément par les CE afin d’identifier de nouvelles cibles thérapeutiques. Nous avons détecté des dépôts de complément, de C3 et de C5b-9, dans des reins de patients souffrants de nephropathie drépanocytaire ainsi que dans un modèle murin de drépanocytose. Nous avons mis en place un modèle murin d’hémolyse intravasculaire massive, déclenchée par la phénylhydrazine (PHZ), et caractérisé l’atteinte rénale. Nous avons détecté des dépôts de C3 au niveau des reins de ces souris. Cet effet a été inhibé par l’administration préventive du scavenger naturel de l’hème, l’hémopexine (Hx), et reproduit par des injections d’hème libre, démontrant une activation hème-dépendante in vivo. Les microvésicules d’érythrocytes (MVs) drépanocytaires représentent une source naturelle d’hème, de par leur concentration en hème trois fois supérieure à celle observée chez les donneurs sains. Nous avons démontré que les MVs drépanocytaires activent le complément dans le sérum et sur les CE, de manière en partie hème-dépendante. Ces résultats révèlent le rôle activateur de l’hème sur le complément dans les maladies hémolytiques. De plus, nous avons démontré que l’interaction de l’hème avec TLR4 peut en partie expliquer les dépôts de C3 sur l’endothélium in vivo et les CE in vitro. L’utilisation d’un inhibiteur de TLR4, le TAK-242, a réduit de 50% les dépôts de complément sur les CE, confirmé par une réduction des dépôts sur l’endothélium vasculaire chez des souris TLR4-/- traitées par PHZ ou hème. De plus, nous avons montré que ces dépôts hème/TLR4 dépendants sont liés à l’expression rapide de P-sélectine, qui recrute C3b et C3(H2O) à la membrane des CE, révélé par l’analyse des interactions protéiques en temps réel et l’utilisation d’un anticorps bloquant anti-P-sélectine. Ensemble, ce projet démontre que l’hème et les MVs sont les produits dérivés de l’hémolyse responsables de l’activation du complément. Au niveau cellulaire, l’induction par l’hème d’un phénotype activateur du complément des CE dépend de l’axe TLR4/P-sélectine, induisant des dépôts de C3 à la surface cellulaire. Ainsi, ces études soulignent les bénéfices potentiels de l’Hx et du TAK-242 contre l’activation du complément dans des pathologies associées à une hémolyse. / Complement system is a complex and tightly regulated innate immune defensive cascade, which can promote tissue damage, when overactivated. Hemolysis-derived danger associated molecular pattern heme is able to activate complement in serum and on endothelial cells (EC) in vitro, providing a rational for scrutinizing the impact of complement activation in hemolytic diseases. The objectives of this work were to study whether and how intravascular hemolysis induces complement activation in vivo, and to understand the underlying mechanism that leads to the acquisition of a complement activating phenotype of the endothelium in order to identify novel therapeutic strategies. We found complement deposits, including C3 activation fragments and C5b-9, within kidneys of patients with sickle cell disease (SCD) nephropathy (a prototypical hemolytic disease) as well as in a mouse model of SCD. We set up and characterized the renal injury of a mouse model of massive intravascular hemolysis, triggered by injection of phenylhydrazine (PHZ). We revealed C3 deposition within kidneys of the PHZ-treated animals. It was prevented by heme scavenging with hemopexin (Hx) and reproduced by injections of free heme, thus demonstrating the importance of heme for the complement activation in vivo. SCD erythrocytes microvesicles (MVs), are a pathologically relevant source of labile heme, since they carry three times more heme on their surface compare to MVs from healthy donors. We demonstrated that MVs, generated from SCD erythrocytes, activate complement in human serum and on EC surface, in part on a heme-dependent manner. These data highlight the importance of heme as a complement activator in hemolytic diseases. Further, we found that the C3 activation fragments deposits on endothelium in vivo and on EC in vitro can be in part explained by interaction of heme with TLR4. Indeed, the use of a specific inhibitor of TLR4, TAK-242, reduced about 50% the complement deposits on EC surface and such deposits on vascular endothelium in PHZ- or heme-injected mice were attenuated TLR4-/- mice. Moreover, we found that heme/TLR4-dependent complement deposition was mediated by the rapid expression of P-selectin, which in turn, recruited C3b and C3(H2O) on the EC surface, as evidenced by real time protein interaction analyses and using of blocking antibodies. Together our results demonstrated that heme and erythrocytes MVs are the hemolysis-derived products which promoted complement activation. At cellular level, heme induced complement-activating phenotype of EC by triggering TLR4/P-selectin axis and resulting in C3 activation fragments on cell surface. Together, these studies underline the potential benefits of Hx and TAK-242 against complement activation in pathologies related to hemolysis.

Η υψηλή συχνότητα εμφάνισης της ηλικιακής εκφύλισης της ωχράς κηλίδας σε συνδυασμό με τις σοβαρές επιπτώσεις της στην υγεία των ασθενών και την αδυναμία πλήρους θεραπευτικής αποκατάστασης της όρασης, καθιστά αναγκαία την διερεύνηση των παθογενετικών μηχανισμών της με στόχο την ανάπτυξη νέων προληπτικών και θεραπευτικών προσσεγγίσεων. Είναι ευρέως αποδεκτό ότι η ηλιακή εκφύλιση της ωχράς κηλίδας είναι μια πολυπαραγοντική ασθένεια στην εμφάνιση της οποίας ενέχονται τόσο αλληλεπιδράσεις περιβάλλοντος-γονιδίων όσο και αλληλεπιδράσεις γονιδίων-γονιδίων. Η αναγνώριση γονιδίων και γενετικών πολυμορφισμών που συμβάλλουν στην επιδεκτικότητα για την εμφάνιση της ασθένειας μπορούν αφενός να συμβάλλουν στην διαλεύκανση της μοριακής παθογένειας αφετέρου να χρησιμοποιηθούν ως γενετικοί δείκτες αυξημένου κινδύνου εμφάνισης οδηγώντας σε νέες προληπτικές και θεραπευτικές προσεγγίσεις. Στόχος της παρούσας εργασίας είναι να διαπιστωθεί εάν οι πολυμορφισμοί Y402H του γονιδίου CFH και A69S του γονιδίου LOC387715 είναι μοριακοί δείκτες επιδεκτικότητας για την ηλικιακή εκφύλιση της ωχράς κηλίδας στον Ελληνικό πληθυσμό της Νοτιοδυτικής Ελλάδας. Η κλινική μελέτη συσχέτισης στην οποία περιλαμβάνει 100 ασθενείς με προχωρημένη AMD και 115 μάρτυρες από τον γενικό πληθυσμό. / -

Η ΒΥΠ διαθέτει αντίτυπο της διατριβής σε έντυπη μορφή στο βιβλιοστάσιο διδακτορικών διατριβών που βρίσκεται στο ισόγειο του κτιρίου της. / Το σύστημα του συμπληρώματος περιλαμβάνει πάνω από 30 πρωτεΐνες του πλάσματος (διαλυτές και υποδοχείς) και παίζει σημαντικό ρόλο, τόσο στη φυσική όσο και στην προσαρμοστική ανοσία. Το συμπλήρωμα ενεργοποιείται μέσω τριών οδών, της κλασσικής, της εναλλακτικής και της λεκτινικής, καταλήγοντας σε κάθε περίπτωση, μέσω της λυτικής οδού, στη διαμόρφωση ενός τελικού συμπλόκου, που λύει το παθογόνο. Τα συστατικά του συμπληρώματος τα οποία απαρτίζουν το τελικό σύμπλοκο MAC, και συμμετέχουν έτσι στη λυτική οδό, είναι τα C5b, C6, C7, C8α, C8β, C8γ και C9. Προκειμένου να μελετήσουμε την μοριακή εξέλιξη της λυτικής οδού του συμπληρώματος κλωνοποιήσαμε και χαρακτηρίσαμε την α και γ υπομονάδα του όγδοου συστατικού του συμπληρώματος στην ιριδίζουσα πέστροφα. Τα cDNA που προέκυψαν για τα C8α και C8γ ήταν 2.037 και 977 νουκλεοτίδια, αντίστοιχα, ενώ η συναγόμενη αμινοξική αλληλουχία ήταν 615 και 221 αμινοξέα, αντίστοιχα. Τα δύο μόρια παρόλο που αλληλεπιδρούν άμεσα και δευσμεύονται επι του συμπλόκου MAC, ανήκουν σε διαφορετικές πρωτεϊνικές οικογένειες. Η μοριακές τους δομές ομοιάζουν με τις αντίστοιχες των μορίων των θηλαστικών και οι αμινοξικές τους αλληλουχίες παρουσιάζουν σημαντικό βαθμό συντήρησης. Στην πέστροφα, το C8α δείχνει να εκφράζεται κύρια στο ήπαρ και στο νεφρό, ενώ το C8γ εκφράζεται επιπλέον και στον ιστό της καρδιάς και της σπλήνας. Ανάλυση κατά Southern έδειξε πως τα δύο γονίδια συναντώνται ως μοναδικά αντίγραφα στο γονιδίωμα της ιριδίζουσας πέστροφας. Αξίζει, τέλος, να σημειωθεί οτι αυτή είναι η πρώτη αναφορά για την κλωνοποίηση της α και γ υπομονάδας του όγδοου συστατικού του συμπληρώματος στα κατώτερα σπονδυλωτά. / The complement system consists of 30 and more proteins present in blood and cell membranes and plays an important role in host defense by interacting with components of both innate and adaptive immunity. It is activated through three distinct activation pathways: the antibody-dependent classical pathway and the alternative and lectin pathways, which are activated by direct binding of complement components to microbial surfaces. Unlike mammalian and other species, teleost are the only organisms that reveal a completely developed and extended complement system, via gene duplication and functional diversity. Complement activation via the classical, lectin, or alternative pathway leads to the formation of the (pore forming) membrane attack complex (MAC) on the surface of complement-opsonized cells. The assembly of MAC involves the aggregation of the lytic complement components C5b, C6, C7, C8α, C8β, C8γ, and C9. In order to elucidate the phylogeny of the lytic pathway of complement we now report the cloning and characterization of the C8α and C8γ genes in rainbow trout (Oncorhynchus mykiss). The deduced amino acid sequence of the trout C8α gene exhibits 44 and 43% identity with human and frog orthologs, respectively. The domain architecture of the trout C8α resembles that of mammalian orthologs, and the cysteine backbone shows a high degree of conservation. The trout C8α shows a similar expression profile with that of trout C8β and C8γ, pointing to the liver as the main source of the C8α gene expression. Although the presence of a fully developed lytic pathway of complement system is expected in teleost, this is the first report of the C8α gene in an organism other than mammalian. The deduced amino acid sequence of trout C8γ shows significant identity (37%) to the human C8γ homolog and much lower to the other known lipocalins. The lipocalin domain is present and all the cysteine residues are conserved. The trout C8γ gene is probably present as a single copy in the trout genome showing a differential expression pattern among tissues investigated. This is the first report the C8α and C8γ genes in an organism other than mammalian.